Unset QT_PLUGIN_PATH. This avoids Qt version mismatches when QT_PLUGIN_PATH is set on the host. This is often the case on NixOS.

Author: JulianGro

src/deployment.h

@@ -110,7 +110,12 @@ inline bool createAppRunHook(appdir::AppDir &appDir) {
         << "    *GNOME*|*gnome*|*XFCE*)" << std::endl
         << "        export QT_QPA_PLATFORMTHEME=" << (haveGtk3 ? "gtk3" : "gtk2") << std::endl
         << "        ;;" << std::endl
-        << "esac" << std::endl;
+        << "esac" << std::endl
+        << std::endl
+        << "# Override QT_PLUGIN_PATH to fall back to defaults. NixOS sets QT_PLUGIN_PATH," << std::endl
+        << "# which causes AppImages with Qt to try and load system Qt plugins." << std::endl
+        << "# This usually fails due to the mismatched Qt versions." << std::endl
+        << "unset QT_PLUGIN_PATH" << std::endl;
 
     return true;
 }