Hello @Roger Rüegg
Please check if this thread helps.
According to here:
This behavior may occur if Word determines that the owner file for the document already exists.
This may occur if one or more of the following conditions are true:
Word previously quit improperly and, therefore, did not delete the owner file.
-or-
A second instance of Word is running in the background with the document already open.
-or-
The document is shared over a network, and another user has it open.
7 Ways To Fix Excel File Is Locked For Editing By Another User Issue
Best Regards
Karlie
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