Do the following: Close the problem document. Create a new file and insert the problem document via the Insert File dialog box. This clears document protection and you can edit the file again.

To display the Insert File dialog box, click the Insert tab, click the arrow on the Object button, and finally choose Text from File. (Note that the "Text from File" command is misleading, because it lets you add all document content, not just text.)

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional