Hello coffee_is_life,
sorry for the delay.
I tried your suggestion but without success.
I could fix the problem now with a new store. Have made a backup to pst, removed the store, create a new store and restored the backup from pst.
Then i created a new outlook profile, because outlook still shows the old store. It’s a online connection, looks like outlook cached it.
Now the user is happy again ;-)
Thanks!
Best regards
Frank