Index: /trunk/src/VBox/Main/src-server/MachineImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/MachineImpl.cpp	(revision 38013)
+++ /trunk/src/VBox/Main/src-server/MachineImpl.cpp	(revision 38014)
@@ -7516,5 +7516,7 @@
     if (FAILED(rc)) return rc;
 
-    /* Read the extra data items. */
+    /* Copy the extra data items (Not in any case config is already the same as
+     * mData->pMachineConfigFile, like when the xml files are read from disk. So
+     * make sure the extra data map is copied). */
     mData->pMachineConfigFile->mapExtraDataItems = config.mapExtraDataItems;