Hi,
I am not yet willing to give up.

Let me explain the effect in more detail.
When I said “the model seems to be locked” I meant the following:
I can open any diagram and rearrange elements. I can edit the elements’ appearance and pull in existing elements from other packages as links or instances. What does no longer work, is adding new elements.
To me this appears as if there is a locking issue in the model database.
Is there any way to get hold on some log or trace information on what happens in the EA model database?