Hi @Peishan Guo,
Try this method and re-set Word custom settings.
- Close Word.
- Press the Win + R:
%appdata%\Microsoft\Templates
- Move or rename Normal.dotm.
- Open and close Word. A new Normal.dotm file is created.
After this method if this issue is still existed, you can do an online repair for Office:
https://support.microsoft.com/en-us/office/repair-an-office-application-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b
Just checking in to see if the information was helpful. Please let us know if you would like further assistance.
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