Index: /trunk/src/VBox/Main/MachineImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/MachineImpl.cpp	(revision 26199)
+++ /trunk/src/VBox/Main/MachineImpl.cpp	(revision 26200)
@@ -2975,4 +2975,5 @@
             medium->attachTo(mData->mUuid);
         pAttach->updateMedium(medium, false /* aImplicit */);
+        setModified(IsModified_Storage);
     }
 
Index: /trunk/src/VBox/Main/MediumAttachmentImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/MediumAttachmentImpl.cpp	(revision 26199)
+++ /trunk/src/VBox/Main/MediumAttachmentImpl.cpp	(revision 26200)
@@ -358,8 +358,7 @@
 }
 
-/** Must be called from under this object's AND the machine's write lock. */
+/** Must be called from under this object's write lock. */
 void MediumAttachment::updateMedium(const ComObjPtr<Medium> &aMedium, bool aImplicit)
 {
-    Assert(m->pMachine->isWriteLockOnCurrentThread());
     Assert(isWriteLockOnCurrentThread());
 
@@ -367,18 +366,13 @@
     m->bd->pMedium = aMedium;
     m->bd->fImplicit = aImplicit;
-
-    m->pMachine->setModified(Machine::IsModified_Storage);
-}
-
-/** Must be called from under this object's AND the machine's write lock. */
+}
+
+/** Must be called from under this object's write lock. */
 void MediumAttachment::updatePassthrough(bool aPassthrough)
 {
-    Assert(m->pMachine->isWriteLockOnCurrentThread());
     Assert(isWriteLockOnCurrentThread());
 
     m->bd.backup();
     m->bd->fPassthrough = aPassthrough;
-
-    m->pMachine->setModified(Machine::IsModified_Storage);
-}
-
+}
+