diff --git a/launcher/minecraft/mod/ResourcePack.h b/launcher/minecraft/mod/ResourcePack.h
index f214bedf2..45883c259 100644
--- a/launcher/minecraft/mod/ResourcePack.h
+++ b/launcher/minecraft/mod/ResourcePack.h
@@ -24,5 +24,5 @@ class ResourcePack : public DataPack {
     /** Gets, respectively, the lower and upper versions supported by the set pack format. */
     [[nodiscard]] std::pair<Version, Version> compatibleVersions() const override;
 
-    virtual QString directory() { return "/assets"; }
+    virtual QString directory() override { return "/assets"; }
 };
diff --git a/launcher/modplatform/atlauncher/ATLPackIndex.h b/launcher/modplatform/atlauncher/ATLPackIndex.h
index 187bc05ec..0df5e237c 100644
--- a/launcher/modplatform/atlauncher/ATLPackIndex.h
+++ b/launcher/modplatform/atlauncher/ATLPackIndex.h
@@ -45,3 +45,4 @@ void loadIndexedPack(IndexedPack& m, QJsonObject& obj);
 }  // namespace ATLauncher
 
 Q_DECLARE_METATYPE(ATLauncher::IndexedPack)
+Q_DECLARE_METATYPE(QList<ATLauncher::IndexedVersion>)
\ No newline at end of file
diff --git a/launcher/modplatform/flame/FlamePackIndex.h b/launcher/modplatform/flame/FlamePackIndex.h
index 30391288b..d2cf2a6aa 100644
--- a/launcher/modplatform/flame/FlamePackIndex.h
+++ b/launcher/modplatform/flame/FlamePackIndex.h
@@ -50,3 +50,4 @@ void loadIndexedPackVersions(IndexedPack& m, QJsonArray& arr);
 }  // namespace Flame
 
 Q_DECLARE_METATYPE(Flame::IndexedPack)
+Q_DECLARE_METATYPE(QList<Flame::IndexedVersion>)
diff --git a/launcher/modplatform/modrinth/ModrinthPackManifest.h b/launcher/modplatform/modrinth/ModrinthPackManifest.h
index 97b8ab712..6d970b264 100644
--- a/launcher/modplatform/modrinth/ModrinthPackManifest.h
+++ b/launcher/modplatform/modrinth/ModrinthPackManifest.h
@@ -124,3 +124,4 @@ auto validateDownloadUrl(QUrl) -> bool;
 
 Q_DECLARE_METATYPE(Modrinth::Modpack)
 Q_DECLARE_METATYPE(Modrinth::ModpackVersion)
+Q_DECLARE_METATYPE(QList<Modrinth::ModpackVersion>)
diff --git a/launcher/ui/pages/instance/McResolver.cpp b/launcher/ui/pages/instance/McResolver.cpp
index 2a769762c..5e2b8239c 100644
--- a/launcher/ui/pages/instance/McResolver.cpp
+++ b/launcher/ui/pages/instance/McResolver.cpp
@@ -37,9 +37,9 @@ void McResolver::pingWithDomainSRV(QString domain, int port)
         }
 
         const auto& firstRecord = records.at(0);
-        QString domain = firstRecord.target();
-        int port = firstRecord.port();
-        pingWithDomainA(domain, port);
+        QString newDomain = firstRecord.target();
+        int newPort = firstRecord.port();
+        pingWithDomainA(newDomain, newPort);
     });
 
     lookup->lookup();
diff --git a/launcher/ui/pages/modplatform/atlauncher/AtlFilterModel.cpp b/launcher/ui/pages/modplatform/atlauncher/AtlFilterModel.cpp
index dee3784e5..6868ce736 100644
--- a/launcher/ui/pages/modplatform/atlauncher/AtlFilterModel.cpp
+++ b/launcher/ui/pages/modplatform/atlauncher/AtlFilterModel.cpp
@@ -68,7 +68,10 @@ bool FilterModel::filterAcceptsRow(int sourceRow, const QModelIndex& sourceParen
         return true;
     }
     QModelIndex index = sourceModel()->index(sourceRow, 0, sourceParent);
-    ATLauncher::IndexedPack pack = sourceModel()->data(index, Qt::UserRole).value<ATLauncher::IndexedPack>();
+    QVariant raw = sourceModel()->data(index, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<ATLauncher::IndexedPack>());
+    auto pack = raw.value<ATLauncher::IndexedPack>();
+
     if (searchTerm.startsWith("#"))
         return QString::number(pack.id) == searchTerm.mid(1);
     return pack.name.contains(searchTerm, Qt::CaseInsensitive);
@@ -76,8 +79,12 @@ bool FilterModel::filterAcceptsRow(int sourceRow, const QModelIndex& sourceParen
 
 bool FilterModel::lessThan(const QModelIndex& left, const QModelIndex& right) const
 {
-    ATLauncher::IndexedPack leftPack = sourceModel()->data(left, Qt::UserRole).value<ATLauncher::IndexedPack>();
-    ATLauncher::IndexedPack rightPack = sourceModel()->data(right, Qt::UserRole).value<ATLauncher::IndexedPack>();
+    QVariant leftRaw = sourceModel()->data(left, Qt::UserRole);
+    Q_ASSERT(leftRaw.canConvert<ATLauncher::IndexedPack>());
+    auto leftPack = leftRaw.value<ATLauncher::IndexedPack>();
+    QVariant rightRaw = sourceModel()->data(right, Qt::UserRole);
+    Q_ASSERT(rightRaw.canConvert<ATLauncher::IndexedPack>());
+    auto rightPack = rightRaw.value<ATLauncher::IndexedPack>();
 
     if (currentSorting == ByPopularity) {
         return leftPack.position > rightPack.position;
diff --git a/launcher/ui/pages/modplatform/atlauncher/AtlPage.cpp b/launcher/ui/pages/modplatform/atlauncher/AtlPage.cpp
index 7c69b315e..ad49d940e 100644
--- a/launcher/ui/pages/modplatform/atlauncher/AtlPage.cpp
+++ b/launcher/ui/pages/modplatform/atlauncher/AtlPage.cpp
@@ -143,7 +143,9 @@ void AtlPage::onSelectionChanged(QModelIndex first, [[maybe_unused]] QModelIndex
         return;
     }
 
-    selected = filterModel->data(first, Qt::UserRole).value<ATLauncher::IndexedPack>();
+    QVariant raw = filterModel->data(first, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<ATLauncher::IndexedPack>());
+    selected = raw.value<ATLauncher::IndexedPack>();
 
     ui->packDescription->setHtml(StringUtils::htmlListPatch(selected.description.replace("\n", "<br>")));
 
diff --git a/launcher/ui/pages/modplatform/flame/FlameModel.cpp b/launcher/ui/pages/modplatform/flame/FlameModel.cpp
index d501bf9f4..5562e34b8 100644
--- a/launcher/ui/pages/modplatform/flame/FlameModel.cpp
+++ b/launcher/ui/pages/modplatform/flame/FlameModel.cpp
@@ -79,6 +79,7 @@ bool ListModel::setData(const QModelIndex& index, const QVariant& value, [[maybe
     if (pos >= modpacks.size() || pos < 0 || !index.isValid())
         return false;
 
+    Q_ASSERT(value.canConvert<Flame::IndexedPack>());
     modpacks[pos] = value.value<Flame::IndexedPack>();
 
     return true;
diff --git a/launcher/ui/pages/modplatform/flame/FlamePage.cpp b/launcher/ui/pages/modplatform/flame/FlamePage.cpp
index bb91e5a64..015cc165e 100644
--- a/launcher/ui/pages/modplatform/flame/FlamePage.cpp
+++ b/launcher/ui/pages/modplatform/flame/FlamePage.cpp
@@ -166,7 +166,9 @@ void FlamePage::onSelectionChanged(QModelIndex curr, [[maybe_unused]] QModelInde
         return;
     }
 
-    current = listModel->data(curr, Qt::UserRole).value<Flame::IndexedPack>();
+    QVariant raw = listModel->data(curr, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Flame::IndexedPack>());
+    current = raw.value<Flame::IndexedPack>();
 
     if (!current.versionsLoaded || m_filterWidget->changed()) {
         qDebug() << "Loading flame modpack versions";
diff --git a/launcher/ui/pages/modplatform/import_ftb/ImportFTBPage.cpp b/launcher/ui/pages/modplatform/import_ftb/ImportFTBPage.cpp
index 15303bb22..35e1dc110 100644
--- a/launcher/ui/pages/modplatform/import_ftb/ImportFTBPage.cpp
+++ b/launcher/ui/pages/modplatform/import_ftb/ImportFTBPage.cpp
@@ -103,13 +103,16 @@ void ImportFTBPage::suggestCurrent()
     dialog->setSuggestedIconFromFile(FS::PathCombine(selected.path, "folder.jpg"), editedLogoName);
 }
 
-void ImportFTBPage::onPublicPackSelectionChanged(QModelIndex now, QModelIndex prev)
+void ImportFTBPage::onPublicPackSelectionChanged(QModelIndex now, QModelIndex)
 {
     if (!now.isValid()) {
         onPackSelectionChanged();
         return;
     }
-    Modpack selectedPack = currentModel->data(now, Qt::UserRole).value<Modpack>();
+
+    QVariant raw = currentModel->data(now, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modpack>());
+    auto selectedPack = raw.value<Modpack>();
     onPackSelectionChanged(&selectedPack);
 }
 
diff --git a/launcher/ui/pages/modplatform/import_ftb/ListModel.cpp b/launcher/ui/pages/modplatform/import_ftb/ListModel.cpp
index f99ac8d65..8d3beea01 100644
--- a/launcher/ui/pages/modplatform/import_ftb/ListModel.cpp
+++ b/launcher/ui/pages/modplatform/import_ftb/ListModel.cpp
@@ -143,8 +143,12 @@ FilterModel::FilterModel(QObject* parent) : QSortFilterProxyModel(parent)
 
 bool FilterModel::lessThan(const QModelIndex& left, const QModelIndex& right) const
 {
-    Modpack leftPack = sourceModel()->data(left, Qt::UserRole).value<Modpack>();
-    Modpack rightPack = sourceModel()->data(right, Qt::UserRole).value<Modpack>();
+    QVariant leftRaw = sourceModel()->data(left, Qt::UserRole);
+    Q_ASSERT(leftRaw.canConvert<Modpack>());
+    auto leftPack = leftRaw.value<Modpack>();
+    QVariant rightRaw = sourceModel()->data(right, Qt::UserRole);
+    Q_ASSERT(rightRaw.canConvert<Modpack>());
+    auto rightPack = rightRaw.value<Modpack>();
 
     if (m_currentSorting == Sorting::ByGameVersion) {
         Version lv(leftPack.mcVersion);
@@ -166,7 +170,9 @@ bool FilterModel::filterAcceptsRow([[maybe_unused]] int sourceRow, [[maybe_unuse
         return true;
     }
     QModelIndex index = sourceModel()->index(sourceRow, 0, sourceParent);
-    Modpack pack = sourceModel()->data(index, Qt::UserRole).value<Modpack>();
+    QVariant raw = sourceModel()->data(index, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modpack>());
+    auto pack = raw.value<Modpack>();
     return pack.name.contains(m_searchTerm, Qt::CaseInsensitive);
 }
 
diff --git a/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp b/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp
index b68fcd34a..97960845d 100644
--- a/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp
+++ b/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp
@@ -61,8 +61,12 @@ FilterModel::FilterModel(QObject* parent) : QSortFilterProxyModel(parent)
 
 bool FilterModel::lessThan(const QModelIndex& left, const QModelIndex& right) const
 {
-    Modpack leftPack = sourceModel()->data(left, Qt::UserRole).value<Modpack>();
-    Modpack rightPack = sourceModel()->data(right, Qt::UserRole).value<Modpack>();
+    QVariant leftRaw = sourceModel()->data(left, Qt::UserRole);
+    Q_ASSERT(leftRaw.canConvert<Modpack>());
+    auto leftPack = leftRaw.value<Modpack>();
+    QVariant rightRaw = sourceModel()->data(right, Qt::UserRole);
+    Q_ASSERT(rightRaw.canConvert<Modpack>());
+    auto rightPack = rightRaw.value<Modpack>();
 
     if (currentSorting == Sorting::ByGameVersion) {
         Version lv(leftPack.mcVersion);
@@ -84,7 +88,9 @@ bool FilterModel::filterAcceptsRow([[maybe_unused]] int sourceRow, [[maybe_unuse
         return true;
     }
     QModelIndex index = sourceModel()->index(sourceRow, 0, sourceParent);
-    Modpack pack = sourceModel()->data(index, Qt::UserRole).value<Modpack>();
+    QVariant raw = sourceModel()->data(index, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modpack>());
+    auto pack = raw.value<Modpack>();
     if (searchTerm.startsWith("#"))
         return pack.packCode == searchTerm.mid(1);
     return pack.name.contains(searchTerm, Qt::CaseInsensitive);
diff --git a/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp b/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp
index 5752b6c61..1576f52fe 100644
--- a/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp
+++ b/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp
@@ -233,7 +233,9 @@ void Page::onPublicPackSelectionChanged(QModelIndex now, [[maybe_unused]] QModel
         onPackSelectionChanged();
         return;
     }
-    Modpack selectedPack = publicFilterModel->data(now, Qt::UserRole).value<Modpack>();
+    QVariant raw = publicFilterModel->data(now, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modpack>());
+    auto selectedPack = raw.value<Modpack>();
     onPackSelectionChanged(&selectedPack);
 }
 
@@ -243,7 +245,9 @@ void Page::onThirdPartyPackSelectionChanged(QModelIndex now, [[maybe_unused]] QM
         onPackSelectionChanged();
         return;
     }
-    Modpack selectedPack = thirdPartyFilterModel->data(now, Qt::UserRole).value<Modpack>();
+    QVariant raw = thirdPartyFilterModel->data(now, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modpack>());
+    auto selectedPack = raw.value<Modpack>();
     onPackSelectionChanged(&selectedPack);
 }
 
@@ -253,7 +257,9 @@ void Page::onPrivatePackSelectionChanged(QModelIndex now, [[maybe_unused]] QMode
         onPackSelectionChanged();
         return;
     }
-    Modpack selectedPack = privateFilterModel->data(now, Qt::UserRole).value<Modpack>();
+    QVariant raw = privateFilterModel->data(now, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modpack>());
+    auto selectedPack = raw.value<Modpack>();
     onPackSelectionChanged(&selectedPack);
 }
 
@@ -328,7 +334,9 @@ void Page::onTabChanged(int tab)
     currentList->selectionModel()->reset();
     QModelIndex idx = currentList->currentIndex();
     if (idx.isValid()) {
-        auto pack = currentModel->data(idx, Qt::UserRole).value<Modpack>();
+        QVariant raw = currentModel->data(idx, Qt::UserRole);
+        Q_ASSERT(raw.canConvert<Modpack>());
+        auto pack = raw.value<Modpack>();
         onPackSelectionChanged(&pack);
     } else {
         onPackSelectionChanged();
diff --git a/launcher/ui/pages/modplatform/modrinth/ModrinthModel.cpp b/launcher/ui/pages/modplatform/modrinth/ModrinthModel.cpp
index 4681b1a7f..323300af9 100644
--- a/launcher/ui/pages/modplatform/modrinth/ModrinthModel.cpp
+++ b/launcher/ui/pages/modplatform/modrinth/ModrinthModel.cpp
@@ -121,6 +121,7 @@ bool ModpackListModel::setData(const QModelIndex& index, const QVariant& value,
     if (pos >= modpacks.size() || pos < 0 || !index.isValid())
         return false;
 
+    Q_ASSERT(value.canConvert<Modrinth::Modpack>());
     modpacks[pos] = value.value<Modrinth::Modpack>();
 
     return true;
@@ -137,7 +138,7 @@ void ModpackListModel::performPaginatedSearch()
             ResourceAPI::ProjectInfoCallbacks callbacks;
 
             callbacks.on_fail = [this](QString reason) { searchRequestFailed(reason); };
-            callbacks.on_succeed = [this](auto& doc, auto& pack) { searchRequestForOneSucceeded(doc); };
+            callbacks.on_succeed = [this](auto& doc, auto&) { searchRequestForOneSucceeded(doc); };
             callbacks.on_abort = [this] {
                 qCritical() << "Search task aborted by an unknown reason!";
                 searchRequestFailed("Aborted");
@@ -345,7 +346,7 @@ void ModpackListModel::searchRequestForOneSucceeded(QJsonDocument& doc)
     endInsertRows();
 }
 
-void ModpackListModel::searchRequestFailed(QString reason)
+void ModpackListModel::searchRequestFailed(QString)
 {
     auto failed_action = dynamic_cast<NetJob*>(jobPtr.get())->getFailedActions().at(0);
     if (failed_action->replyStatusCode() == -1) {
diff --git a/launcher/ui/pages/modplatform/modrinth/ModrinthPage.cpp b/launcher/ui/pages/modplatform/modrinth/ModrinthPage.cpp
index 701bb9f72..f8214e8bb 100644
--- a/launcher/ui/pages/modplatform/modrinth/ModrinthPage.cpp
+++ b/launcher/ui/pages/modplatform/modrinth/ModrinthPage.cpp
@@ -150,7 +150,9 @@ void ModrinthPage::onSelectionChanged(QModelIndex curr, [[maybe_unused]] QModelI
         return;
     }
 
-    current = m_model->data(curr, Qt::UserRole).value<Modrinth::Modpack>();
+    QVariant raw = m_model->data(curr, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Modrinth::Modpack>());
+    current = raw.value<Modrinth::Modpack>();
     auto name = current.name;
 
     if (!current.extraInfoLoaded) {
diff --git a/launcher/ui/pages/modplatform/technic/TechnicData.h b/launcher/ui/pages/modplatform/technic/TechnicData.h
index 11d57f071..1049d1f2e 100644
--- a/launcher/ui/pages/modplatform/technic/TechnicData.h
+++ b/launcher/ui/pages/modplatform/technic/TechnicData.h
@@ -36,6 +36,7 @@
 #pragma once
 
 #include <QList>
+#include <QMetaType>
 #include <QString>
 
 namespace Technic {
diff --git a/launcher/ui/pages/modplatform/technic/TechnicPage.cpp b/launcher/ui/pages/modplatform/technic/TechnicPage.cpp
index 50d267b1f..6319eb06e 100644
--- a/launcher/ui/pages/modplatform/technic/TechnicPage.cpp
+++ b/launcher/ui/pages/modplatform/technic/TechnicPage.cpp
@@ -135,7 +135,9 @@ void TechnicPage::onSelectionChanged(QModelIndex first, [[maybe_unused]] QModelI
         return;
     }
 
-    current = model->data(first, Qt::UserRole).value<Technic::Modpack>();
+    QVariant raw = model->data(first, Qt::UserRole);
+    Q_ASSERT(raw.canConvert<Technic::Modpack>());
+    current = raw.value<Technic::Modpack>();
     suggestCurrent();
 }
 
diff --git a/tests/FileSystem_test.cpp b/tests/FileSystem_test.cpp
index 995867e46..8aa25d82d 100644
--- a/tests/FileSystem_test.cpp
+++ b/tests/FileSystem_test.cpp
@@ -69,7 +69,9 @@ class LinkTask : public Task {
     }
 
     FS::create_link* m_lnk;
-    [[maybe_unused]] bool m_useHard = false;
+#if defined Q_OS_WIN32
+    bool m_useHard = false;
+#endif
     bool m_linkRecursive = true;
 };