Hi @Anhalter42 ,
Please check as follows:
- Antivirus programs may open potentially unsafe files as read-only.Check with your antivirus provider to learn how to adjust these settings. For convenient test, please temporarily turn off the antivirus software to check the result.
- If you have libraries with Checkout, Required, or Validation columns or metadata, or when Draft Item Security is set to either Only users who can edit or Only users who can approve items in Version Settings of the library, these items will be synchronized as read-only.
- If Office is not activated, or if your subscription has expired, you might be in read-only Reduced Functionality Mode. For information on how to Activate Office, see Unlicensed Product and activation errors in Office.
- Right-click the file and choose Properties. If the Read-only attribute is checked, uncheck it and select OK.
More information:
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