diff --git a/src/base/CMakeLists.txt b/src/base/CMakeLists.txt
index 67238b4e8..1b96f61f2 100644
--- a/src/base/CMakeLists.txt
+++ b/src/base/CMakeLists.txt
@@ -17,7 +17,7 @@ add_library(qbt_base STATIC
     bittorrent/infohash.h
     bittorrent/loadtorrentparams.h
     bittorrent/ltqhash.h
-    bittorrent/ltunderlyingtype.h
+    bittorrent/lttypecast.h
     bittorrent/magneturi.h
     bittorrent/nativesessionextension.h
     bittorrent/nativetorrentextension.h
diff --git a/src/base/base.pri b/src/base/base.pri
index 401f7b9bd..57af3dbd6 100644
--- a/src/base/base.pri
+++ b/src/base/base.pri
@@ -16,7 +16,7 @@ HEADERS += \
     $$PWD/bittorrent/infohash.h \
     $$PWD/bittorrent/loadtorrentparams.h \
     $$PWD/bittorrent/ltqhash.h \
-    $$PWD/bittorrent/ltunderlyingtype.h \
+    $$PWD/bittorrent/lttypecast.h \
     $$PWD/bittorrent/magneturi.h \
     $$PWD/bittorrent/nativesessionextension.h \
     $$PWD/bittorrent/nativetorrentextension.h \
diff --git a/src/base/bittorrent/abstractfilestorage.h b/src/base/bittorrent/abstractfilestorage.h
index b13cb5b52..74afda94f 100644
--- a/src/base/bittorrent/abstractfilestorage.h
+++ b/src/base/bittorrent/abstractfilestorage.h
@@ -44,7 +44,6 @@ namespace BitTorrent
 
         virtual int filesCount() const = 0;
         virtual QString filePath(int index) const = 0;
-        virtual QString fileName(int index) const = 0;
         virtual qlonglong fileSize(int index) const = 0;
 
         virtual void renameFile(int index, const QString &name) = 0;
diff --git a/src/base/bittorrent/ltunderlyingtype.h b/src/base/bittorrent/lttypecast.h
similarity index 65%
rename from src/base/bittorrent/ltunderlyingtype.h
rename to src/base/bittorrent/lttypecast.h
index 6b3993b2d..53d96f155 100644
--- a/src/base/bittorrent/ltunderlyingtype.h
+++ b/src/base/bittorrent/lttypecast.h
@@ -1,6 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
- * Copyright (C) 2019  Vladimir Golovnev <glassez@yandex.ru>
+ * Copyright (C) 2019, 2021  Vladimir Golovnev <glassez@yandex.ru>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -28,8 +28,25 @@
 
 #pragma once
 
-template <typename T>
-typename T::underlying_type toLTUnderlyingType(const T &t)
+#include <libtorrent/download_priority.hpp>
+
+#include "downloadpriority.h"
+
+namespace BitTorrent::LT
 {
-    return static_cast<typename T::underlying_type>(t);
+    template <typename T>
+    constexpr typename T::underlying_type toUnderlyingType(const T &t) noexcept
+    {
+        return static_cast<typename T::underlying_type>(t);
+    }
+
+    constexpr lt::download_priority_t toNative(const DownloadPriority priority) noexcept
+    {
+        return static_cast<lt::download_priority_t>(static_cast<lt::download_priority_t::underlying_type>(priority));
+    }
+
+    constexpr DownloadPriority fromNative(const lt::download_priority_t priority) noexcept
+    {
+        return static_cast<DownloadPriority>(toUnderlyingType(priority));
+    }
 }
diff --git a/src/base/bittorrent/session.cpp b/src/base/bittorrent/session.cpp
index 22726ff07..dd846fedb 100644
--- a/src/base/bittorrent/session.cpp
+++ b/src/base/bittorrent/session.cpp
@@ -93,7 +93,7 @@
 #include "filesearcher.h"
 #include "filterparserthread.h"
 #include "loadtorrentparams.h"
-#include "ltunderlyingtype.h"
+#include "lttypecast.h"
 #include "magneturi.h"
 #include "nativesessionextension.h"
 #include "portforwarderimpl.h"
@@ -1491,7 +1491,7 @@ void Session::configurePeerClasses()
     // Proactively do the same for 0.0.0.0 and address_v4::any()
     f.add_rule(lt::address_v4::any()
                , lt::address_v4::broadcast()
-               , 1 << toLTUnderlyingType(lt::session::global_peer_class_id));
+               , 1 << LT::toUnderlyingType(lt::session::global_peer_class_id));
 
     // IPv6 may not be available on OS and the parsing
     // would result in an exception -> abnormal program termination
@@ -1500,7 +1500,7 @@ void Session::configurePeerClasses()
     {
         f.add_rule(lt::address_v6::any()
                    , lt::make_address("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
-                   , 1 << toLTUnderlyingType(lt::session::global_peer_class_id));
+                   , 1 << LT::toUnderlyingType(lt::session::global_peer_class_id));
     }
     catch (const std::exception &) {}
 
@@ -1509,21 +1509,21 @@ void Session::configurePeerClasses()
         // local networks
         f.add_rule(lt::make_address("10.0.0.0")
                    , lt::make_address("10.255.255.255")
-                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                   , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
         f.add_rule(lt::make_address("172.16.0.0")
                    , lt::make_address("172.31.255.255")
-                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                   , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
         f.add_rule(lt::make_address("192.168.0.0")
                    , lt::make_address("192.168.255.255")
-                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                   , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
         // link local
         f.add_rule(lt::make_address("169.254.0.0")
                    , lt::make_address("169.254.255.255")
-                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                   , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
         // loopback
         f.add_rule(lt::make_address("127.0.0.0")
                    , lt::make_address("127.255.255.255")
-                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                   , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
 
         // IPv6 may not be available on OS and the parsing
         // would result in an exception -> abnormal program termination
@@ -1533,15 +1533,15 @@ void Session::configurePeerClasses()
             // link local
             f.add_rule(lt::make_address("fe80::")
                        , lt::make_address("febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
-                       , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                       , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
             // unique local addresses
             f.add_rule(lt::make_address("fc00::")
                        , lt::make_address("fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
-                       , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                       , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
             // loopback
             f.add_rule(lt::address_v6::loopback()
                        , lt::address_v6::loopback()
-                       , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
+                       , 1 << LT::toUnderlyingType(lt::session::local_peer_class_id));
         }
         catch (const std::exception &) {}
     }
@@ -1727,8 +1727,10 @@ void Session::fileSearchFinished(const TorrentID &id, const QString &savePath, c
         lt::add_torrent_params &p = params.ltAddTorrentParams;
 
         p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
+        const TorrentInfo torrentInfo {p.ti};
+        const auto nativeIndexes = torrentInfo.nativeIndexes();
         for (int i = 0; i < fileNames.size(); ++i)
-            p.renamed_files[lt::file_index_t {i}] = fileNames[i].toStdString();
+            p.renamed_files[nativeIndexes[i]] = fileNames[i].toStdString();
 
         loadTorrent(params);
     }
@@ -2141,28 +2143,20 @@ bool Session::addTorrent_impl(const std::variant<MagnetUri, TorrentInfo> &source
         {
             QString contentName = metadata.rootFolder();
             if (contentName.isEmpty() && (metadata.filesCount() == 1))
-                contentName = metadata.fileName(0);
+                contentName = Utils::Fs::fileName(metadata.filePath(0));
 
             if (!contentName.isEmpty() && (contentName != metadata.name()))
                 loadTorrentParams.name = contentName;
         }
 
         Q_ASSERT(p.file_priorities.empty());
-        if (addTorrentParams.filePriorities.empty())
-        {
-            // Use qBittorrent default priority rather than libtorrent's (4)
-            p.file_priorities = std::vector(metadata.filesCount(), static_cast<lt::download_priority_t>(
-                    static_cast<lt::download_priority_t::underlying_type>(DownloadPriority::Normal)));
-        }
-        else
-        {
-            std::transform(addTorrentParams.filePriorities.cbegin(), addTorrentParams.filePriorities.cend()
-                           , std::back_inserter(p.file_priorities), [](const DownloadPriority priority)
-            {
-                return static_cast<lt::download_priority_t>(
-                        static_cast<lt::download_priority_t::underlying_type>(priority));
-            });
-        }
+        const int internalFilesCount = metadata.nativeInfo()->files().num_files(); // including .pad files
+        // Use qBittorrent default priority rather than libtorrent's (4)
+        p.file_priorities = std::vector(internalFilesCount, LT::toNative(DownloadPriority::Normal));
+        const auto nativeIndexes = metadata.nativeIndexes();
+        Q_ASSERT(addTorrentParams.filePriorities.isEmpty() || (addTorrentParams.filePriorities.size() == nativeIndexes.size()));
+        for (int i = 0; i < addTorrentParams.filePriorities.size(); ++i)
+            p.file_priorities[LT::toUnderlyingType(nativeIndexes[i])] = LT::toNative(addTorrentParams.filePriorities[i]);
 
         p.ti = metadata.nativeInfo();
     }
@@ -2388,7 +2382,7 @@ void Session::saveTorrentsQueue() const
     for (const TorrentImpl *torrent : asConst(m_torrents))
     {
         // We require actual (non-cached) queue position here!
-        const int queuePos = toLTUnderlyingType(torrent->nativeHandle().queue_position());
+        const int queuePos = LT::toUnderlyingType(torrent->nativeHandle().queue_position());
         if (queuePos >= 0)
         {
             if (queuePos >= queue.size())
@@ -3937,9 +3931,8 @@ void Session::handleTorrentFinished(TorrentImpl *const torrent)
 
     qDebug("Checking if the torrent contains torrent files to download");
     // Check if there are torrent files inside
-    for (int i = 0; i < torrent->filesCount(); ++i)
+    for (const QString &torrentRelpath : asConst(torrent->filePaths()))
     {
-        const QString torrentRelpath = torrent->filePath(i);
         if (torrentRelpath.endsWith(".torrent", Qt::CaseInsensitive))
         {
             qDebug("Found possible recursive torrent download.");
@@ -4162,9 +4155,8 @@ void Session::recursiveTorrentDownload(const TorrentID &id)
     TorrentImpl *const torrent = m_torrents.value(id);
     if (!torrent) return;
 
-    for (int i = 0; i < torrent->filesCount(); ++i)
+    for (const QString &torrentRelpath : asConst(torrent->filePaths()))
     {
-        const QString torrentRelpath = torrent->filePath(i);
         if (torrentRelpath.endsWith(".torrent"))
         {
             LogMsg(tr("Recursive download of file '%1' embedded in torrent '%2'"
diff --git a/src/base/bittorrent/torrent.h b/src/base/bittorrent/torrent.h
index 0f40dff3f..3c8869d6e 100644
--- a/src/base/bittorrent/torrent.h
+++ b/src/base/bittorrent/torrent.h
@@ -193,6 +193,7 @@ namespace BitTorrent
         virtual qreal ratioLimit() const = 0;
         virtual int seedingTimeLimit() const = 0;
 
+        virtual QStringList filePaths() const = 0;
         virtual QStringList absoluteFilePaths() const = 0;
         virtual QVector<DownloadPriority> filePriorities() const = 0;
 
@@ -214,7 +215,6 @@ namespace BitTorrent
         virtual bool hasMetadata() const = 0;
         virtual bool hasMissingFiles() const = 0;
         virtual bool hasError() const = 0;
-        virtual bool hasFilteredPieces() const = 0;
         virtual int queuePosition() const = 0;
         virtual QVector<TrackerEntry> trackers() const = 0;
         virtual QVector<QUrl> urlSeeds() const = 0;
diff --git a/src/base/bittorrent/torrentcreatorthread.cpp b/src/base/bittorrent/torrentcreatorthread.cpp
index 53aaa3885..80b6cc9b2 100644
--- a/src/base/bittorrent/torrentcreatorthread.cpp
+++ b/src/base/bittorrent/torrentcreatorthread.cpp
@@ -44,7 +44,7 @@
 #include "base/utils/fs.h"
 #include "base/utils/io.h"
 #include "base/version.h"
-#include "ltunderlyingtype.h"
+#include "lttypecast.h"
 
 namespace
 {
@@ -186,7 +186,7 @@ void TorrentCreatorThread::run()
             , [this, &newTorrent](const lt::piece_index_t n)
         {
             checkInterruptionRequested();
-            sendProgressSignal(toLTUnderlyingType(n), newTorrent.num_pieces());
+            sendProgressSignal(LT::toUnderlyingType(n), newTorrent.num_pieces());
         });
 
         // Set qBittorrent as creator and add user comment to
diff --git a/src/base/bittorrent/torrentimpl.cpp b/src/base/bittorrent/torrentimpl.cpp
index 356b14d02..4ffa3ee0b 100644
--- a/src/base/bittorrent/torrentimpl.cpp
+++ b/src/base/bittorrent/torrentimpl.cpp
@@ -64,7 +64,7 @@
 #include "downloadpriority.h"
 #include "loadtorrentparams.h"
 #include "ltqhash.h"
-#include "ltunderlyingtype.h"
+#include "lttypecast.h"
 #include "peeraddress.h"
 #include "peerinfo.h"
 #include "session.h"
@@ -74,20 +74,6 @@ using namespace BitTorrent;
 
 namespace
 {
-    std::vector<lt::download_priority_t> toLTDownloadPriorities(const QVector<DownloadPriority> &priorities)
-    {
-        std::vector<lt::download_priority_t> out;
-        out.reserve(priorities.size());
-
-        std::transform(priorities.cbegin(), priorities.cend()
-                       , std::back_inserter(out), [](const DownloadPriority priority)
-        {
-            return static_cast<lt::download_priority_t>(
-                        static_cast<lt::download_priority_t::underlying_type>(priority));
-        });
-        return out;
-    }
-
     lt::announce_entry makeNativeAnnouncerEntry(const QString &url, const int tier)
     {
         lt::announce_entry entry {url.toStdString()};
@@ -762,20 +748,19 @@ int TorrentImpl::seedingTimeLimit() const
     return m_seedingTimeLimit;
 }
 
-QString TorrentImpl::filePath(int index) const
+QString TorrentImpl::filePath(const int index) const
 {
     return m_torrentInfo.filePath(index);
 }
 
-QString TorrentImpl::fileName(int index) const
+qlonglong TorrentImpl::fileSize(const int index) const
 {
-    if (!hasMetadata()) return {};
-    return Utils::Fs::fileName(filePath(index));
+    return m_torrentInfo.fileSize(index);
 }
 
-qlonglong TorrentImpl::fileSize(int index) const
+QStringList TorrentImpl::filePaths() const
 {
-    return m_torrentInfo.fileSize(index);
+    return m_torrentInfo.filePaths();
 }
 
 // Return a list of absolute paths corresponding
@@ -784,8 +769,9 @@ QStringList TorrentImpl::absoluteFilePaths() const
 {
     if (!hasMetadata()) return {};
 
-    const QDir saveDir(savePath(true));
+    const QDir saveDir {savePath(true)};
     QStringList res;
+    res.reserve(filesCount());
     for (int i = 0; i < filesCount(); ++i)
         res << Utils::Fs::expandPathAbs(saveDir.absoluteFilePath(filePath(i)));
     return res;
@@ -793,14 +779,19 @@ QStringList TorrentImpl::absoluteFilePaths() const
 
 QVector<DownloadPriority> TorrentImpl::filePriorities() const
 {
+    if (!hasMetadata())
+        return {};
+
     const std::vector<lt::download_priority_t> fp = m_nativeHandle.get_file_priorities();
 
     QVector<DownloadPriority> ret;
-    ret.reserve(static_cast<decltype(ret)::size_type>(fp.size()));
-    std::transform(fp.cbegin(), fp.cend(), std::back_inserter(ret), [](const lt::download_priority_t priority)
+    ret.reserve(filesCount());
+    for (const lt::file_index_t nativeIndex : asConst(m_torrentInfo.nativeIndexes()))
     {
-        return static_cast<DownloadPriority>(toLTUnderlyingType(priority));
-    });
+        const auto priority = LT::fromNative(fp[LT::toUnderlyingType(nativeIndex)]);
+        ret.append(priority);
+    }
+
     return ret;
 }
 
@@ -987,15 +978,6 @@ bool TorrentImpl::hasError() const
     return (m_nativeStatus.errc || (m_nativeStatus.flags & lt::torrent_flags::upload_mode));
 }
 
-bool TorrentImpl::hasFilteredPieces() const
-{
-    const std::vector<lt::download_priority_t> pp = m_nativeHandle.get_piece_priorities();
-    return std::any_of(pp.cbegin(), pp.cend(), [](const lt::download_priority_t priority)
-    {
-        return (priority == lt::download_priority_t {0});
-    });
-}
-
 int TorrentImpl::queuePosition() const
 {
     return static_cast<int>(m_nativeStatus.queue_position);
@@ -1092,16 +1074,18 @@ QVector<qreal> TorrentImpl::filesProgress() const
     std::vector<int64_t> fp;
     m_nativeHandle.file_progress(fp, lt::torrent_handle::piece_granularity);
 
-    const int count = static_cast<int>(fp.size());
+    const int count = filesCount();
+    const auto nativeIndexes = m_torrentInfo.nativeIndexes();
     QVector<qreal> result;
     result.reserve(count);
     for (int i = 0; i < count; ++i)
     {
+        const int64_t progress = fp[LT::toUnderlyingType(nativeIndexes[i])];
         const qlonglong size = fileSize(i);
-        if ((size <= 0) || (fp[i] == size))
+        if ((size <= 0) || (progress == size))
             result << 1;
         else
-            result << (fp[i] / static_cast<qreal>(size));
+            result << (progress / static_cast<qreal>(size));
     }
 
     return result;
@@ -1252,7 +1236,7 @@ QBitArray TorrentImpl::downloadingPieces() const
     m_nativeHandle.get_download_queue(queue);
 
     for (const lt::partial_piece_info &info : queue)
-        result.setBit(toLTUnderlyingType(info.piece_index));
+        result.setBit(LT::toUnderlyingType(info.piece_index));
 
     return result;
 }
@@ -1406,7 +1390,7 @@ void TorrentImpl::move_impl(QString path, const MoveStorageMode mode)
     }
 }
 
-void TorrentImpl::forceReannounce(int index)
+void TorrentImpl::forceReannounce(const int index)
 {
     m_nativeHandle.force_reannounce(0, index);
 }
@@ -1469,28 +1453,29 @@ void TorrentImpl::applyFirstLastPiecePriority(const bool enabled, const QVector<
 
     // Download first and last pieces first for every file in the torrent
 
-    const std::vector<lt::download_priority_t> filePriorities = !updatedFilePrio.isEmpty() ? toLTDownloadPriorities(updatedFilePrio)
-                                                                           : nativeHandle().get_file_priorities();
+    const QVector<DownloadPriority> filePriorities =
+            !updatedFilePrio.isEmpty() ? updatedFilePrio : this->filePriorities();
     std::vector<lt::download_priority_t> piecePriorities = nativeHandle().get_piece_priorities();
 
     // Updating file priorities is an async operation in libtorrent, when we just updated it and immediately query it
     // we might get the old/wrong values, so we rely on `updatedFilePrio` in this case.
-    for (int index = 0; index < static_cast<int>(filePriorities.size()); ++index)
+    for (int index = 0; index < filePriorities.size(); ++index)
     {
-        const lt::download_priority_t filePrio = filePriorities[index];
-        if (filePrio <= lt::download_priority_t {0})
+        const DownloadPriority filePrio = filePriorities[index];
+        if (filePrio <= DownloadPriority::Ignored)
             continue;
 
         // Determine the priority to set
-        const lt::download_priority_t newPrio = enabled ? lt::download_priority_t {7} : filePrio;
+        const DownloadPriority newPrio = enabled ? DownloadPriority::Maximum : filePrio;
+        const auto piecePrio = static_cast<lt::download_priority_t>(static_cast<int>(newPrio));
         const TorrentInfo::PieceRange extremities = info().filePieces(index);
 
         // worst case: AVI index = 1% of total file size (at the end of the file)
         const int nNumPieces = std::ceil(fileSize(index) * 0.01 / pieceLength());
         for (int i = 0; i < nNumPieces; ++i)
         {
-            piecePriorities[extremities.first() + i] = newPrio;
-            piecePriorities[extremities.last() - i] = newPrio;
+            piecePriorities[extremities.first() + i] = piecePrio;
+            piecePriorities[extremities.last() - i] = piecePrio;
         }
     }
 
@@ -1506,14 +1491,16 @@ void TorrentImpl::endReceivedMetadataHandling(const QString &savePath, const QSt
 {
     lt::add_torrent_params &p = m_ltAddTorrentParams;
 
-    p.ti = std::const_pointer_cast<lt::torrent_info>(m_nativeHandle.torrent_file());
+    const TorrentInfo torrentInfo {m_nativeHandle.torrent_file()};
+    const auto nativeIndexes = torrentInfo.nativeIndexes();
     for (int i = 0; i < fileNames.size(); ++i)
-        p.renamed_files[lt::file_index_t {i}] = fileNames[i].toStdString();
+        p.renamed_files[nativeIndexes[i]] = fileNames[i].toStdString();
     p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
+    p.ti = torrentInfo.nativeInfo();
 
+    const int internalFilesCount = p.ti->files().num_files(); // including .pad files
     // Use qBittorrent default priority rather than libtorrent's (4)
-    p.file_priorities = std::vector(fileNames.size(), static_cast<lt::download_priority_t>(
-            static_cast<lt::download_priority_t::underlying_type>(DownloadPriority::Normal)));
+    p.file_priorities = std::vector(internalFilesCount, LT::toNative(DownloadPriority::Normal));
 
     reload();
 
@@ -1630,10 +1617,10 @@ void TorrentImpl::renameFile(const int index, const QString &path)
 {
 #ifndef QBT_USES_LIBTORRENT2
     const QString oldPath = filePath(index);
-    m_oldPath[lt::file_index_t {index}].push_back(oldPath);
+    m_oldPath[index].push_back(oldPath);
 #endif
     ++m_renameCount;
-    m_nativeHandle.rename_file(lt::file_index_t {index}, Utils::Fs::toNativePath(path).toStdString());
+    m_nativeHandle.rename_file(m_torrentInfo.nativeIndexes()[index], Utils::Fs::toNativePath(path).toStdString());
 }
 
 void TorrentImpl::handleStateUpdate(const lt::torrent_status &nativeStatus)
@@ -1864,13 +1851,16 @@ void TorrentImpl::handleFastResumeRejectedAlert(const lt::fastresume_rejected_al
 
 void TorrentImpl::handleFileRenamedAlert(const lt::file_renamed_alert *p)
 {
+    const int fileIndex = m_torrentInfo.nativeIndexes().indexOf(p->index);
+    Q_ASSERT(fileIndex >= 0);
+
     // Remove empty leftover folders
     // For example renaming "a/b/c" to "d/b/c", then folders "a/b" and "a" will
     // be removed if they are empty
 #ifndef QBT_USES_LIBTORRENT2
-    const QString oldFilePath = m_oldPath[p->index].takeFirst();
-    if (m_oldPath[p->index].isEmpty())
-        m_oldPath.remove(p->index);
+    const QString oldFilePath = m_oldPath[fileIndex].takeFirst();
+    if (m_oldPath[fileIndex].isEmpty())
+        m_oldPath.remove(fileIndex);
 #else
     const QString oldFilePath = Utils::Fs::toUniformPath(p->old_name());
 #endif
@@ -1910,14 +1900,16 @@ void TorrentImpl::handleFileRenamedAlert(const lt::file_renamed_alert *p)
 
 void TorrentImpl::handleFileRenameFailedAlert(const lt::file_rename_failed_alert *p)
 {
+    const int fileIndex = m_torrentInfo.nativeIndexes().indexOf(p->index);
+    Q_ASSERT(fileIndex >= 0);
+
     LogMsg(tr("File rename failed. Torrent: \"%1\", file: \"%2\", reason: \"%3\"")
-        .arg(name(), filePath(toLTUnderlyingType(p->index))
-             , QString::fromLocal8Bit(p->error.message().c_str())), Log::WARNING);
+        .arg(name(), filePath(fileIndex), QString::fromLocal8Bit(p->error.message().c_str())), Log::WARNING);
 
 #ifndef QBT_USES_LIBTORRENT2
-    m_oldPath[p->index].removeFirst();
-    if (m_oldPath[p->index].isEmpty())
-        m_oldPath.remove(p->index);
+    m_oldPath[fileIndex].removeFirst();
+    if (m_oldPath[fileIndex].isEmpty())
+        m_oldPath.remove(fileIndex);
 #endif
 
     --m_renameCount;
@@ -1929,16 +1921,19 @@ void TorrentImpl::handleFileRenameFailedAlert(const lt::file_rename_failed_alert
 
 void TorrentImpl::handleFileCompletedAlert(const lt::file_completed_alert *p)
 {
+    const int fileIndex = m_torrentInfo.nativeIndexes().indexOf(p->index);
+    Q_ASSERT(fileIndex >= 0);
+
     qDebug("A file completed download in torrent \"%s\"", qUtf8Printable(name()));
     if (m_session->isAppendExtensionEnabled())
     {
-        QString name = filePath(toLTUnderlyingType(p->index));
+        QString name = filePath(fileIndex);
         if (name.endsWith(QB_EXT))
         {
             const QString oldName = name;
             name.chop(QB_EXT.size());
             qDebug("Renaming %s to %s", qUtf8Printable(oldName), qUtf8Printable(name));
-            renameFile(toLTUnderlyingType(p->index), name);
+            renameFile(fileIndex, name);
         }
     }
 }
@@ -2271,7 +2266,8 @@ QString TorrentImpl::createMagnetURI() const
 void TorrentImpl::prioritizeFiles(const QVector<DownloadPriority> &priorities)
 {
     if (!hasMetadata()) return;
-    if (priorities.size() != filesCount()) return;
+
+    Q_ASSERT(priorities.size() == filesCount());
 
     // Reset 'm_hasSeedStatus' if needed in order to react again to
     // 'torrent_finished_alert' and eg show tray notifications
@@ -2288,8 +2284,14 @@ void TorrentImpl::prioritizeFiles(const QVector<DownloadPriority> &priorities)
         }
     }
 
+    const int internalFilesCount = m_torrentInfo.nativeInfo()->files().num_files(); // including .pad files
+    auto nativePriorities = std::vector<lt::download_priority_t>(internalFilesCount, LT::toNative(DownloadPriority::Normal));
+    const auto nativeIndexes = m_torrentInfo.nativeIndexes();
+    for (int i = 0; i < priorities.size(); ++i)
+        nativePriorities[LT::toUnderlyingType(nativeIndexes[i])] = LT::toNative(priorities[i]);
+
     qDebug() << Q_FUNC_INFO << "Changing files priorities...";
-    m_nativeHandle.prioritize_files(toLTDownloadPriorities(priorities));
+    m_nativeHandle.prioritize_files(nativePriorities);
 
     // Restore first/last piece first option if necessary
     if (m_hasFirstLastPiecePriority)
diff --git a/src/base/bittorrent/torrentimpl.h b/src/base/bittorrent/torrentimpl.h
index 696017878..14721e935 100644
--- a/src/base/bittorrent/torrentimpl.h
+++ b/src/base/bittorrent/torrentimpl.h
@@ -126,8 +126,8 @@ namespace BitTorrent
         int seedingTimeLimit() const override;
 
         QString filePath(int index) const override;
-        QString fileName(int index) const override;
         qlonglong fileSize(int index) const override;
+        QStringList filePaths() const override;
         QStringList absoluteFilePaths() const override;
         QVector<DownloadPriority> filePriorities() const override;
 
@@ -149,7 +149,6 @@ namespace BitTorrent
         bool hasMetadata() const override;
         bool hasMissingFiles() const override;
         bool hasError() const override;
-        bool hasFilteredPieces() const override;
         int queuePosition() const override;
         QVector<TrackerEntry> trackers() const override;
         QVector<QUrl> urlSeeds() const override;
@@ -305,7 +304,7 @@ namespace BitTorrent
 #ifndef QBT_USES_LIBTORRENT2
         // Until libtorrent provided an "old_name" field in `file_renamed_alert`
         // we relied on this workaround to remove empty leftover folders
-        QHash<lt::file_index_t, QVector<QString>> m_oldPath;
+        QHash<int, QVector<QString>> m_oldPath;
 #endif
 
         QHash<QString, QMap<lt::tcp::endpoint, int>> m_trackerPeerCounts;
diff --git a/src/base/bittorrent/torrentinfo.cpp b/src/base/bittorrent/torrentinfo.cpp
index 5a1c7bdc7..499c0c96e 100644
--- a/src/base/bittorrent/torrentinfo.cpp
+++ b/src/base/bittorrent/torrentinfo.cpp
@@ -76,12 +76,23 @@ namespace
 const int torrentInfoId = qRegisterMetaType<TorrentInfo>();
 
 TorrentInfo::TorrentInfo(std::shared_ptr<const lt::torrent_info> nativeInfo)
+    : m_nativeInfo {std::const_pointer_cast<lt::torrent_info>(nativeInfo)}
 {
-    m_nativeInfo = std::const_pointer_cast<lt::torrent_info>(nativeInfo);
+    if (!m_nativeInfo)
+        return;
+
+    const lt::file_storage &fileStorage = m_nativeInfo->files();
+    m_nativeIndexes.reserve(fileStorage.num_files());
+    for (const lt::file_index_t nativeIndex : fileStorage.file_range())
+    {
+        if (!fileStorage.pad_file_at(nativeIndex))
+            m_nativeIndexes.append(nativeIndex);
+    }
 }
 
 TorrentInfo::TorrentInfo(const TorrentInfo &other)
-    : m_nativeInfo(other.m_nativeInfo)
+    : m_nativeInfo {other.m_nativeInfo}
+    , m_nativeIndexes {other.m_nativeIndexes}
 {
 }
 
@@ -90,6 +101,7 @@ TorrentInfo &TorrentInfo::operator=(const TorrentInfo &other)
     if (this != &other)
     {
         m_nativeInfo = other.m_nativeInfo;
+        m_nativeIndexes = other.m_nativeIndexes;
     }
     return *this;
 }
@@ -241,7 +253,7 @@ qlonglong TorrentInfo::totalSize() const
 int TorrentInfo::filesCount() const
 {
     if (!isValid()) return -1;
-    return m_nativeInfo->num_files();
+    return m_nativeIndexes.size();
 }
 
 int TorrentInfo::pieceLength() const
@@ -266,40 +278,36 @@ QString TorrentInfo::filePath(const int index) const
 {
     if (!isValid()) return {};
     return Utils::Fs::toUniformPath(
-                QString::fromStdString(m_nativeInfo->files().file_path(lt::file_index_t {index})));
+                QString::fromStdString(m_nativeInfo->files().file_path(m_nativeIndexes[index])));
 }
 
 QStringList TorrentInfo::filePaths() const
 {
     QStringList list;
+    list.reserve(filesCount());
     for (int i = 0; i < filesCount(); ++i)
         list << filePath(i);
 
     return list;
 }
 
-QString TorrentInfo::fileName(const int index) const
-{
-    return Utils::Fs::fileName(filePath(index));
-}
-
 QString TorrentInfo::origFilePath(const int index) const
 {
     if (!isValid()) return {};
     return Utils::Fs::toUniformPath(
-                QString::fromStdString(m_nativeInfo->orig_files().file_path(lt::file_index_t {index})));
+                QString::fromStdString(m_nativeInfo->orig_files().file_path(m_nativeIndexes[index])));
 }
 
 qlonglong TorrentInfo::fileSize(const int index) const
 {
     if (!isValid()) return -1;
-    return m_nativeInfo->files().file_size(lt::file_index_t {index});
+    return m_nativeInfo->files().file_size(m_nativeIndexes[index]);
 }
 
 qlonglong TorrentInfo::fileOffset(const int index) const
 {
     if (!isValid()) return -1;
-    return m_nativeInfo->files().file_offset(lt::file_index_t {index});
+    return m_nativeInfo->files().file_offset(m_nativeIndexes[index]);
 }
 
 QVector<TrackerEntry> TorrentInfo::trackers() const
@@ -368,8 +376,12 @@ QVector<int> TorrentInfo::fileIndicesForPiece(const int pieceIndex) const
                 lt::piece_index_t {pieceIndex}, 0, nativeInfo()->piece_size(lt::piece_index_t {pieceIndex}));
     QVector<int> res;
     res.reserve(static_cast<decltype(res)::size_type>(files.size()));
-    std::transform(files.begin(), files.end(), std::back_inserter(res),
-        [](const lt::file_slice &s) { return static_cast<int>(s.file_index); });
+    for (const lt::file_slice &fileSlice : files)
+    {
+        const int index = m_nativeIndexes.indexOf(fileSlice.file_index);
+        if (index >= 0)
+            res.append(index);
+    }
 
     return res;
 }
@@ -415,8 +427,8 @@ TorrentInfo::PieceRange TorrentInfo::filePieces(const int fileIndex) const
     }
 
     const lt::file_storage &files = nativeInfo()->files();
-    const auto fileSize = files.file_size(lt::file_index_t {fileIndex});
-    const auto fileOffset = files.file_offset(lt::file_index_t {fileIndex});
+    const auto fileSize = files.file_size(m_nativeIndexes[fileIndex]);
+    const auto fileOffset = files.file_offset(m_nativeIndexes[fileIndex]);
 
     const int beginIdx = (fileOffset / pieceLength());
     const int endIdx = ((fileOffset + fileSize - 1) / pieceLength());
@@ -429,7 +441,7 @@ TorrentInfo::PieceRange TorrentInfo::filePieces(const int fileIndex) const
 void TorrentInfo::renameFile(const int index, const QString &newPath)
 {
     if (!isValid()) return;
-    nativeInfo()->rename_file(lt::file_index_t {index}, Utils::Fs::toNativePath(newPath).toStdString());
+    nativeInfo()->rename_file(m_nativeIndexes[index], Utils::Fs::toNativePath(newPath).toStdString());
 }
 
 int TorrentInfo::fileIndex(const QString &fileName) const
@@ -481,8 +493,8 @@ void TorrentInfo::stripRootFolder()
     if (files.name() != newName)
     {
         files.set_name(newName);
-        for (int i = 0; i < files.num_files(); ++i)
-            files.rename_file(lt::file_index_t {i}, files.file_path(lt::file_index_t {i}));
+        for (const lt::file_index_t nativeIndex : files.file_range())
+            files.rename_file(nativeIndex, files.file_path(nativeIndex));
     }
 
     files.set_name("");
@@ -501,8 +513,8 @@ void TorrentInfo::addRootFolder()
     const std::string rootPrefix = Utils::Fs::toNativePath(rootFolder + QLatin1Char {'/'}).toStdString();
     lt::file_storage files = m_nativeInfo->files();
     files.set_name(rootFolder.toStdString());
-    for (int i = 0; i < files.num_files(); ++i)
-        files.rename_file(lt::file_index_t {i}, rootPrefix + files.file_path(lt::file_index_t {i}));
+    for (const lt::file_index_t nativeIndex : files.file_range())
+        files.rename_file(nativeIndex, rootPrefix + files.file_path(nativeIndex));
     m_nativeInfo->remap_files(files);
 }
 
@@ -523,3 +535,8 @@ std::shared_ptr<lt::torrent_info> TorrentInfo::nativeInfo() const
 {
     return m_nativeInfo;
 }
+
+QVector<lt::file_index_t> TorrentInfo::nativeIndexes() const
+{
+    return m_nativeIndexes;
+}
diff --git a/src/base/bittorrent/torrentinfo.h b/src/base/bittorrent/torrentinfo.h
index 781d81952..7aa1cb560 100644
--- a/src/base/bittorrent/torrentinfo.h
+++ b/src/base/bittorrent/torrentinfo.h
@@ -75,7 +75,6 @@ namespace BitTorrent
         int piecesCount() const;
         QString filePath(int index) const override;
         QStringList filePaths() const;
-        QString fileName(int index) const override;
         QString origFilePath(int index) const;
         qlonglong fileSize(int index) const override;
         qlonglong fileOffset(int index) const;
@@ -99,6 +98,7 @@ namespace BitTorrent
         void setContentLayout(TorrentContentLayout layout);
 
         std::shared_ptr<lt::torrent_info> nativeInfo() const;
+        QVector<lt::file_index_t> nativeIndexes() const;
 
     private:
         // returns file index or -1 if fileName is not found
@@ -108,6 +108,10 @@ namespace BitTorrent
         TorrentContentLayout defaultContentLayout() const;
 
         std::shared_ptr<lt::torrent_info> m_nativeInfo;
+
+        // internal indexes of files (payload only, excluding any .pad files)
+        // by which they are addressed in libtorrent
+        QVector<lt::file_index_t> m_nativeIndexes;
     };
 }
 
diff --git a/src/gui/addnewtorrentdialog.cpp b/src/gui/addnewtorrentdialog.cpp
index c9d466313..5dfebf114 100644
--- a/src/gui/addnewtorrentdialog.cpp
+++ b/src/gui/addnewtorrentdialog.cpp
@@ -407,8 +407,10 @@ void AddNewTorrentDialog::updateDiskSpaceLabel()
             const QVector<BitTorrent::DownloadPriority> priorities = m_contentModel->model()->getFilePriorities();
             Q_ASSERT(priorities.size() == m_torrentInfo.filesCount());
             for (int i = 0; i < priorities.size(); ++i)
+            {
                 if (priorities[i] > BitTorrent::DownloadPriority::Ignored)
                     torrentSize += m_torrentInfo.fileSize(i);
+            }
         }
         else
         {
diff --git a/src/gui/previewselectdialog.cpp b/src/gui/previewselectdialog.cpp
index 73f326edb..78bcafa61 100644
--- a/src/gui/previewselectdialog.cpp
+++ b/src/gui/previewselectdialog.cpp
@@ -85,10 +85,9 @@ PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, const BitTorrent::Torr
     m_ui->previewList->setAlternatingRowColors(pref->useAlternatingRowColors());
     // Fill list in
     const QVector<qreal> fp = torrent->filesProgress();
-    int nbFiles = torrent->filesCount();
-    for (int i = 0; i < nbFiles; ++i)
+    for (int i = 0; i <= torrent->filesCount(); ++i)
     {
-        QString fileName = torrent->fileName(i);
+        QString fileName = Utils::Fs::fileName(torrent->filePath(i));
         if (fileName.endsWith(QB_EXT))
             fileName.chop(QB_EXT.length());
         if (Utils::Misc::isPreviewable(fileName))
diff --git a/src/gui/torrentcontentmodel.cpp b/src/gui/torrentcontentmodel.cpp
index 71a3374f7..d99064eb0 100644
--- a/src/gui/torrentcontentmodel.cpp
+++ b/src/gui/torrentcontentmodel.cpp
@@ -283,7 +283,7 @@ bool TorrentContentModel::setData(const QModelIndex &index, const QVariant &valu
     if ((index.column() == TorrentContentModelItem::COL_NAME) && (role == Qt::CheckStateRole))
     {
         auto *item = static_cast<TorrentContentModelItem*>(index.internalPointer());
-        qDebug("setData(%s, %d", qUtf8Printable(item->name()), value.toInt());
+        qDebug("setData(%s, %d)", qUtf8Printable(item->name()), value.toInt());
         if (static_cast<int>(item->priority()) != value.toInt())
         {
             BitTorrent::DownloadPriority prio = BitTorrent::DownloadPriority::Normal;
@@ -349,7 +349,7 @@ QVariant TorrentContentModel::data(const QModelIndex &index, const int role) con
     switch (role)
     {
     case Qt::DecorationRole:
-    {
+        {
             if (index.column() != TorrentContentModelItem::COL_NAME)
                 return {};
 
@@ -358,7 +358,7 @@ QVariant TorrentContentModel::data(const QModelIndex &index, const int role) con
             return m_fileIconProvider->icon(QFileInfo(item->name()));
         }
     case Qt::CheckStateRole:
-    {
+        {
             if (index.column() != TorrentContentModelItem::COL_NAME)
                 return {};
 
@@ -519,7 +519,8 @@ void TorrentContentModel::setupModelData(const BitTorrent::TorrentInfo &info)
             currentParent = newParent;
         }
         // Actually create the file
-        TorrentContentModelFile *fileItem = new TorrentContentModelFile(info.fileName(i), info.fileSize(i), currentParent, i);
+        TorrentContentModelFile *fileItem = new TorrentContentModelFile(
+                    Utils::Fs::fileName(info.filePath(i)), info.fileSize(i), currentParent, i);
         currentParent->appendChild(fileItem);
         m_filesIndex.push_back(fileItem);
     }
diff --git a/src/gui/torrentcontentmodelfolder.cpp b/src/gui/torrentcontentmodelfolder.cpp
index f0b073301..725abc659 100644
--- a/src/gui/torrentcontentmodelfolder.cpp
+++ b/src/gui/torrentcontentmodelfolder.cpp
@@ -139,8 +139,10 @@ void TorrentContentModelFolder::setPriority(BitTorrent::DownloadPriority newPrio
 
     // Update children
     if (m_priority != BitTorrent::DownloadPriority::Mixed)
+    {
         for (TorrentContentModelItem *child : asConst(m_childItems))
             child->setPriority(m_priority, false);
+    }
 }
 
 void TorrentContentModelFolder::recalculateProgress()
diff --git a/src/gui/transferlistwidget.cpp b/src/gui/transferlistwidget.cpp
index e42a144c9..4592ca413 100644
--- a/src/gui/transferlistwidget.cpp
+++ b/src/gui/transferlistwidget.cpp
@@ -91,9 +91,9 @@ namespace
         if (!torrent->hasMetadata())
             return false;
 
-        for (int i = 0; i < torrent->filesCount(); ++i)
+        for (const QString &filePath : asConst(torrent->filePaths()))
         {
-            QString fileName = torrent->fileName(i);
+            QString fileName = Utils::Fs::fileName(filePath);
             if (fileName.endsWith(QB_EXT))
                 fileName.chop(QB_EXT.length());
             if (Utils::Misc::isPreviewable(fileName))