diff --git a/src/frontend/qt_sdl/EmuInstance.cpp b/src/frontend/qt_sdl/EmuInstance.cpp
index f690bdb8..309abe66 100644
--- a/src/frontend/qt_sdl/EmuInstance.cpp
+++ b/src/frontend/qt_sdl/EmuInstance.cpp
@@ -29,7 +29,6 @@
 #include <fstream>
 
 #include <QDateTime>
-#include <QMessageBox>
 
 #include <zstd.h>
 #ifdef ARCHIVE_SUPPORT_ENABLED
@@ -1457,16 +1456,22 @@ void EmuInstance::reset()
 }
 
 
-bool EmuInstance::bootToMenu()
+bool EmuInstance::bootToMenu(QString& errorstr)
 {
     // Keep whatever cart is in the console, if any.
     if (!updateConsole())
+    {
         // Try to update the console, but keep the existing cart. If that fails...
+        errorstr = "Failed to boot the firmware.";
         return false;
+    }
 
     // BIOS and firmware files are loaded, patched, and installed in UpdateConsole
     if (nds->NeedsDirectBoot())
+    {
+        errorstr = "This firmware is not bootable.";
         return false;
+    }
 
     initFirmwareSaveManager();
     nds->Reset();
@@ -1843,7 +1848,7 @@ QString EmuInstance::getSavErrorString(std::string& filepath, bool gba)
     return QString::fromStdString(err1);
 }
 
-bool EmuInstance::loadROM(QStringList filepath, bool reset)
+bool EmuInstance::loadROM(QStringList filepath, bool reset, QString& errorstr)
 {
     unique_ptr<u8[]> filedata = nullptr;
     u32 filelen;
@@ -1852,7 +1857,7 @@ bool EmuInstance::loadROM(QStringList filepath, bool reset)
 
     if (!loadROMData(filepath, filedata, filelen, basepath, romname))
     {
-        QMessageBox::critical(mainWindow, "melonDS", "Failed to load the DS ROM.");
+        errorstr = "Failed to load the DS ROM.";
         return false;
     }
 
@@ -1874,7 +1879,7 @@ bool EmuInstance::loadROM(QStringList filepath, bool reset)
     {
         if (!Platform::CheckFileWritable(origsav))
         {
-            QMessageBox::critical(mainWindow, "melonDS", getSavErrorString(origsav, false));
+            errorstr = getSavErrorString(origsav, false);
             return false;
         }
 
@@ -1882,7 +1887,7 @@ bool EmuInstance::loadROM(QStringList filepath, bool reset)
     }
     else if (!Platform::CheckFileWritable(savname))
     {
-        QMessageBox::critical(mainWindow, "melonDS", getSavErrorString(savname, false));
+        errorstr = getSavErrorString(savname, false);
         return false;
     }
 
@@ -1909,7 +1914,7 @@ bool EmuInstance::loadROM(QStringList filepath, bool reset)
     if (!cart)
     {
         // If we couldn't parse the ROM...
-        QMessageBox::critical(mainWindow, "melonDS", "Failed to load the DS ROM.");
+        errorstr = "Failed to load the DS ROM.";
         return false;
     }
 
@@ -1920,7 +1925,7 @@ bool EmuInstance::loadROM(QStringList filepath, bool reset)
 
         if (!updateConsole())
         {
-            QMessageBox::critical(mainWindow, "melonDS", "Failed to load the DS ROM.");
+            errorstr = "Failed to load the DS ROM.";
             return false;
         }
 
@@ -1996,11 +2001,11 @@ QString EmuInstance::cartLabel()
 }
 
 
-bool EmuInstance::loadGBAROM(QStringList filepath)
+bool EmuInstance::loadGBAROM(QStringList filepath, QString& errorstr)
 {
     if (consoleType == 1)
     {
-        QMessageBox::critical(mainWindow, "melonDS", "The DSi doesn't have a GBA slot.");
+        errorstr = "The DSi doesn't have a GBA slot.";
         return false;
     }
 
@@ -2011,7 +2016,7 @@ bool EmuInstance::loadGBAROM(QStringList filepath)
 
     if (!loadROMData(filepath, filedata, filelen, basepath, romname))
     {
-        QMessageBox::critical(mainWindow, "melonDS", "Failed to load the GBA ROM.");
+        errorstr = "Failed to load the GBA ROM.";
         return false;
     }
 
@@ -2033,7 +2038,7 @@ bool EmuInstance::loadGBAROM(QStringList filepath)
     {
         if (!Platform::CheckFileWritable(origsav))
         {
-            QMessageBox::critical(mainWindow, "melonDS", getSavErrorString(origsav, true));
+            errorstr = getSavErrorString(origsav, true);
             return false;
         }
 
@@ -2041,7 +2046,7 @@ bool EmuInstance::loadGBAROM(QStringList filepath)
     }
     else if (!Platform::CheckFileWritable(savname))
     {
-        QMessageBox::critical(mainWindow, "melonDS", getSavErrorString(savname, true));
+        errorstr = getSavErrorString(savname, true);
         return false;
     }
 
@@ -2061,7 +2066,7 @@ bool EmuInstance::loadGBAROM(QStringList filepath)
     auto cart = GBACart::ParseROM(std::move(filedata), filelen, std::move(savedata), savelen, this);
     if (!cart)
     {
-        QMessageBox::critical(mainWindow, "melonDS", "Failed to load the GBA ROM.");
+        errorstr = "Failed to load the GBA ROM.";
         return false;
     }
 
@@ -2080,14 +2085,14 @@ bool EmuInstance::loadGBAROM(QStringList filepath)
     return true;
 }
 
-void EmuInstance::loadGBAAddon(int type)
+void EmuInstance::loadGBAAddon(int type, QString& errorstr)
 {
     if (consoleType == 1) return;
 
     auto cart = GBACart::LoadAddon(type, this);
     if (!cart)
     {
-        QMessageBox::critical(mainWindow, "melonDS", "Failed to load the GBA addon.");
+        errorstr = "Failed to load the GBA addon.";
         return;
     }
 
diff --git a/src/frontend/qt_sdl/EmuInstance.h b/src/frontend/qt_sdl/EmuInstance.h
index 35943492..48e4e5b9 100644
--- a/src/frontend/qt_sdl/EmuInstance.h
+++ b/src/frontend/qt_sdl/EmuInstance.h
@@ -182,7 +182,7 @@ private:
     std::optional<melonDS::FATStorage> loadSDCard(const std::string& key) noexcept;
     void setBatteryLevels();
     void reset();
-    bool bootToMenu();
+    bool bootToMenu(QString& errorstr);
     melonDS::u32 decompressROM(const melonDS::u8* inContent, const melonDS::u32 inSize, std::unique_ptr<melonDS::u8[]>& outContent);
     void clearBackupState();
     std::pair<std::unique_ptr<melonDS::Firmware>, std::string> generateDefaultFirmware();
@@ -191,13 +191,13 @@ private:
 
     bool loadROMData(const QStringList& filepath, std::unique_ptr<melonDS::u8[]>& filedata, melonDS::u32& filelen, std::string& basepath, std::string& romname) noexcept;
     QString getSavErrorString(std::string& filepath, bool gba);
-    bool loadROM(QStringList filepath, bool reset);
+    bool loadROM(QStringList filepath, bool reset, QString& errorstr);
     void ejectCart();
     bool cartInserted();
     QString cartLabel();
 
-    bool loadGBAROM(QStringList filepath);
-    void loadGBAAddon(int type);
+    bool loadGBAROM(QStringList filepath, QString& errorstr);
+    void loadGBAAddon(int type, QString& errorstr);
     void ejectGBACart();
     bool gbaCartInserted();
     QString gbaAddonName(int addon);
diff --git a/src/frontend/qt_sdl/EmuThread.cpp b/src/frontend/qt_sdl/EmuThread.cpp
index a7feffce..88e20238 100644
--- a/src/frontend/qt_sdl/EmuThread.cpp
+++ b/src/frontend/qt_sdl/EmuThread.cpp
@@ -577,7 +577,7 @@ void EmuThread::handleMessages()
 
         case msg_BootROM:
             msgResult = 0;
-            if (!emuInstance->loadROM(msg.param.value<QStringList>(), true))
+            if (!emuInstance->loadROM(msg.param.value<QStringList>(), true, msgError))
                 break;
 
             assert(emuInstance->nds != nullptr);
@@ -587,7 +587,7 @@ void EmuThread::handleMessages()
 
         case msg_BootFirmware:
             msgResult = 0;
-            if (!emuInstance->bootToMenu())
+            if (!emuInstance->bootToMenu(msgError))
                 break;
 
             assert(emuInstance->nds != nullptr);
@@ -597,7 +597,7 @@ void EmuThread::handleMessages()
 
         case msg_InsertCart:
             msgResult = 0;
-            if (!emuInstance->loadROM(msg.param.value<QStringList>(), false))
+            if (!emuInstance->loadROM(msg.param.value<QStringList>(), false, msgError))
                 break;
 
             msgResult = 1;
@@ -609,7 +609,7 @@ void EmuThread::handleMessages()
 
         case msg_InsertGBACart:
             msgResult = 0;
-            if (!emuInstance->loadGBAROM(msg.param.value<QStringList>()))
+            if (!emuInstance->loadGBAROM(msg.param.value<QStringList>(), msgError))
                 break;
 
             msgResult = 1;
@@ -617,7 +617,7 @@ void EmuThread::handleMessages()
 
         case msg_InsertGBAAddon:
             msgResult = 0;
-            emuInstance->loadGBAAddon(msg.param.value<int>());
+            emuInstance->loadGBAAddon(msg.param.value<int>(), msgError);
             msgResult = 1;
             break;
 
@@ -753,36 +753,45 @@ bool EmuThread::emuIsActive()
     return emuActive;
 }
 
-int EmuThread::bootROM(const QStringList& filename)
+int EmuThread::bootROM(const QStringList& filename, QString& errorstr)
 {
     sendMessage({.type = msg_BootROM, .param = filename});
     waitMessage();
     if (!msgResult)
+    {
+        errorstr = msgError;
         return msgResult;
+    }
 
     sendMessage(msg_EmuRun);
     waitMessage();
+    errorstr = "";
     return msgResult;
 }
 
-int EmuThread::bootFirmware()
+int EmuThread::bootFirmware(QString& errorstr)
 {
     sendMessage(msg_BootFirmware);
     waitMessage();
     if (!msgResult)
+    {
+        errorstr = msgError;
         return msgResult;
+    }
 
     sendMessage(msg_EmuRun);
     waitMessage();
+    errorstr = "";
     return msgResult;
 }
 
-int EmuThread::insertCart(const QStringList& filename, bool gba)
+int EmuThread::insertCart(const QStringList& filename, bool gba, QString& errorstr)
 {
     MessageType msgtype = gba ? msg_InsertGBACart : msg_InsertCart;
 
     sendMessage({.type = msgtype, .param = filename});
     waitMessage();
+    errorstr = msgResult ? "" : msgError;
     return msgResult;
 }
 
@@ -792,10 +801,11 @@ void EmuThread::ejectCart(bool gba)
     waitMessage();
 }
 
-int EmuThread::insertGBAAddon(int type)
+int EmuThread::insertGBAAddon(int type, QString& errorstr)
 {
     sendMessage({.type = msg_InsertGBAAddon, .param = type});
     waitMessage();
+    errorstr = msgResult ? "" : msgError;
     return msgResult;
 }
 
diff --git a/src/frontend/qt_sdl/EmuThread.h b/src/frontend/qt_sdl/EmuThread.h
index 9fa95f3e..61212553 100644
--- a/src/frontend/qt_sdl/EmuThread.h
+++ b/src/frontend/qt_sdl/EmuThread.h
@@ -111,11 +111,11 @@ public:
     void emuFrameStep();
     void emuReset();
 
-    int bootROM(const QStringList& filename);
-    int bootFirmware();
-    int insertCart(const QStringList& filename, bool gba);
+    int bootROM(const QStringList& filename, QString& errorstr);
+    int bootFirmware(QString& errorstr);
+    int insertCart(const QStringList& filename, bool gba, QString& errorstr);
     void ejectCart(bool gba);
-    int insertGBAAddon(int type);
+    int insertGBAAddon(int type, QString& errorstr);
 
     int saveState(const QString& filename);
     int loadState(const QString& filename);
@@ -179,6 +179,7 @@ private:
     int emuPauseStack;
 
     int msgResult = 0;
+    QString msgError;
 
     QMutex msgMutex;
     QSemaphore msgSemaphore;
diff --git a/src/frontend/qt_sdl/Window.cpp b/src/frontend/qt_sdl/Window.cpp
index 71e4f15a..a80b385c 100644
--- a/src/frontend/qt_sdl/Window.cpp
+++ b/src/frontend/qt_sdl/Window.cpp
@@ -986,10 +986,12 @@ void MainWindow::dropEvent(QDropEvent* event)
     isNdsRom |= ZstdNdsRomByExtension(filename);
     isGbaRom |= ZstdGbaRomByExtension(filename);
 
+    QString errorstr;
     if (isNdsRom)
     {
-        if (!emuThread->bootROM(file))
+        if (!emuThread->bootROM(file, errorstr))
         {
+            QMessageBox::critical(this, "melonDS", errorstr);
             return;
         }
 
@@ -1002,8 +1004,9 @@ void MainWindow::dropEvent(QDropEvent* event)
     }
     else if (isGbaRom)
     {
-        if (!emuThread->insertCart(file, true))
+        if (!emuThread->insertCart(file, true, errorstr))
         {
+            QMessageBox::critical(this, "melonDS", errorstr);
             return;
         }
 
@@ -1071,6 +1074,8 @@ bool MainWindow::verifySetup()
 
 bool MainWindow::preloadROMs(QStringList file, QStringList gbafile, bool boot)
 {
+    QString errorstr;
+
     if (file.isEmpty() && gbafile.isEmpty())
         return false;
 
@@ -1082,8 +1087,11 @@ bool MainWindow::preloadROMs(QStringList file, QStringList gbafile, bool boot)
     bool gbaloaded = false;
     if (!gbafile.isEmpty())
     {
-        if (!emuThread->insertCart(gbafile, true))
+        if (!emuThread->insertCart(gbafile, true, errorstr))
+        {
+            QMessageBox::critical(this, "melonDS", errorstr);
             return false;
+        }
 
         gbaloaded = true;
     }
@@ -1093,13 +1101,19 @@ bool MainWindow::preloadROMs(QStringList file, QStringList gbafile, bool boot)
     {
         if (boot)
         {
-            if (!emuThread->bootROM(file))
+            if (!emuThread->bootROM(file, errorstr))
+            {
+                QMessageBox::critical(this, "melonDS", errorstr);
                 return false;
+            }
         }
         else
         {
-            if (!emuThread->insertCart(file, false))
+            if (!emuThread->insertCart(file, false, errorstr))
+            {
+                QMessageBox::critical(this, "melonDS", errorstr);
                 return false;
+            }
         }
         
         recentFileList.removeAll(file.join("|"));
@@ -1109,8 +1123,11 @@ bool MainWindow::preloadROMs(QStringList file, QStringList gbafile, bool boot)
     }
     else if (boot)
     {
-        if (!emuThread->bootFirmware())
+        if (!emuThread->bootFirmware(errorstr))
+        {
+            QMessageBox::critical(this, "melonDS", errorstr);
             return false;
+        }
     }
 
     updateCartInserted(false);
@@ -1308,8 +1325,10 @@ void MainWindow::onOpenFile()
     if (file.isEmpty())
         return;
 
-    if (!emuThread->bootROM(file))
+    QString errorstr;
+    if (!emuThread->bootROM(file, errorstr))
     {
+        QMessageBox::critical(this, "melonDS", errorstr);
         return;
     }
 
@@ -1419,8 +1438,10 @@ void MainWindow::onClickRecentFile()
     if (file.isEmpty())
         return;
 
-    if (!emuThread->bootROM(file))
+    QString errorstr;
+    if (!emuThread->bootROM(file, errorstr))
     {
+        QMessageBox::critical(this, "melonDS", errorstr);
         return;
     }
 
@@ -1436,9 +1457,10 @@ void MainWindow::onBootFirmware()
     if (!verifySetup())
         return;
 
-    if (!emuThread->bootFirmware())
+    QString errorstr;
+    if (!emuThread->bootFirmware(errorstr))
     {
-        QMessageBox::critical(this, "melonDS", "This firmware is not bootable.");
+        QMessageBox::critical(this, "melonDS", errorstr);
         return;
     }
 }
@@ -1449,8 +1471,10 @@ void MainWindow::onInsertCart()
     if (file.isEmpty())
         return;
 
-    if (!emuThread->insertCart(file, false))
+    QString errorstr;
+    if (!emuThread->insertCart(file, false, errorstr))
     {
+        QMessageBox::critical(this, "melonDS", errorstr);
         return;
     }
 
@@ -1469,8 +1493,10 @@ void MainWindow::onInsertGBACart()
     if (file.isEmpty())
         return;
 
-    if (!emuThread->insertCart(file, true))
+    QString errorstr;
+    if (!emuThread->insertCart(file, true, errorstr))
     {
+        QMessageBox::critical(this, "melonDS", errorstr);
         return;
     }
 
@@ -1482,7 +1508,13 @@ void MainWindow::onInsertGBAAddon()
     QAction* act = (QAction*)sender();
     int type = act->data().toInt();
 
-    emuThread->insertGBAAddon(type);
+    QString errorstr;
+    if (!emuThread->insertGBAAddon(type, errorstr))
+    {
+        QMessageBox::critical(this, "melonDS", errorstr);
+        return;
+    }
+
     updateCartInserted(true);
 }