diff --git a/src/gui/DatabaseTabWidget.cpp b/src/gui/DatabaseTabWidget.cpp
index c3afcf06f..21c367b8f 100644
--- a/src/gui/DatabaseTabWidget.cpp
+++ b/src/gui/DatabaseTabWidget.cpp
@@ -155,11 +155,12 @@ void DatabaseTabWidget::addDatabaseTab(const QString& filePath,
                                        const QString& password,
                                        const QString& keyfile)
 {
-    QFileInfo fileInfo(filePath);
+    QString cleanFilePath = QDir::toNativeSeparators(filePath);
+    QFileInfo fileInfo(cleanFilePath);
     QString canonicalFilePath = fileInfo.canonicalFilePath();
 
     if (canonicalFilePath.isEmpty()) {
-        emit messageGlobal(tr("Failed to open %1. It either does not exist or is not accessible.").arg(filePath),
+        emit messageGlobal(tr("Failed to open %1. It either does not exist or is not accessible.").arg(cleanFilePath),
                            MessageWidget::Error);
         return;
     }
@@ -178,10 +179,10 @@ void DatabaseTabWidget::addDatabaseTab(const QString& filePath,
         }
     }
 
-    auto* dbWidget = new DatabaseWidget(QSharedPointer<Database>::create(filePath), this);
+    auto* dbWidget = new DatabaseWidget(QSharedPointer<Database>::create(cleanFilePath), this);
     addDatabaseTab(dbWidget, inBackground);
     dbWidget->performUnlockDatabase(password, keyfile);
-    updateLastDatabases(filePath);
+    updateLastDatabases(cleanFilePath);
 }
 
 /**
@@ -782,7 +783,7 @@ void DatabaseTabWidget::updateLastDatabases(const QString& filename)
         config()->remove(Config::LastDatabases);
     } else {
         QStringList lastDatabases = config()->get(Config::LastDatabases).toStringList();
-        lastDatabases.prepend(filename);
+        lastDatabases.prepend(QDir::toNativeSeparators(filename));
         lastDatabases.removeDuplicates();
 
         while (lastDatabases.count() > config()->get(Config::NumberOfRememberedLastDatabases).toInt()) {
diff --git a/src/main.cpp b/src/main.cpp
index 9fabf89ed..047e44740 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -44,6 +44,10 @@ Q_IMPORT_PLUGIN(QXcbIntegrationPlugin)
 #endif
 #endif
 
+#ifdef Q_OS_WIN
+#include <windows.h>
+#endif
+
 int main(int argc, char** argv)
 {
     QT_REQUIRE_VERSION(argc, argv, QT_VERSION_STR)
@@ -110,9 +114,29 @@ int main(int argc, char** argv)
         Config::createConfigFromFile(parser.value(configOption), parser.value(localConfigOption));
     }
 
+    // Extract file names provided on the command line for opening
+    QStringList fileNames;
+#ifdef Q_OS_WIN
+    // Get correct case for Windows filenames (fixes #7139)
+    for (const auto& file : parser.positionalArguments()) {
+        const auto fileInfo = QFileInfo(file);
+        WIN32_FIND_DATA findFileData;
+        HANDLE hFind;
+        hFind = FindFirstFile(fileInfo.absoluteFilePath().toUtf8(), &findFileData);
+        if (hFind != INVALID_HANDLE_VALUE) {
+            fileNames << QString("%1/%2").arg(fileInfo.absolutePath(), QString::fromUtf8(findFileData.cFileName));
+            FindClose(hFind);
+        }
+    }
+#else
+    for (const auto& file : parser.positionalArguments()) {
+        if (QFile::exists(file)) {
+            fileNames << QDir::toNativeSeparators(file);
+        }
+    }
+#endif
+
     // Process single instance and early exit if already running
-    // FIXME: this is a *mess* and it is entirely my fault. --wundrweapon
-    const QStringList fileNames = parser.positionalArguments();
     if (app.isAlreadyRunning()) {
         if (parser.isSet(lockOption)) {
             if (app.sendLockToInstance()) {
@@ -179,10 +203,7 @@ int main(int argc, char** argv)
             out << QObject::tr("Database password: ") << flush;
             password = Utils::getPassword();
         }
-
-        if (!filename.isEmpty() && QFile::exists(filename) && !filename.endsWith(".json", Qt::CaseInsensitive)) {
-            mainWindow.openDatabase(QDir::toNativeSeparators(filename), password, parser.value(keyfileOption));
-        }
+        mainWindow.openDatabase(filename, password, parser.value(keyfileOption));
     }
 
     int exitCode = Application::exec();