--- a/src/qml/common/qv4compileddata.cpp
+++ b/src/qml/common/qv4compileddata.cpp
@@ -178,6 +178,14 @@ bool CompilationUnit::saveToDisk(const QUrl &unitUrl, QString *errorString)
         return false;
     }
 
+    if (unitUrl.path().startsWith(QStringLiteral("@nixStore@"))) {
+        // We don't store bytecode for bare QML files in the nix store as the
+        // paths will change every time the application updates, filling caches
+        // endlessly with junk.
+        *errorString = QStringLiteral("Refusing to save bytecode for bare @nixStore@ path.");
+        return false;
+    }
+
     return SaveableUnitPointer(unitData()).saveToDisk<char>(
             [&unitUrl, errorString](const char *data, quint32 size) {
                 const QString cachePath = localCacheFilePath(unitUrl);