It appears that something is preventing you from saving to the Normal template. That "something" must be troubleshot separately, but, as a workaround, you can do the following: From within Word, press Alt+F11; the Visual Basic Editor displays. Press Ctrl+G to activate the Immediate window. Type

NormalTemplate.OpenAsDocument

and press Enter. Normal opens in a separate window (and you should now close the Visual Basic Editor). Change the defaults on the Set Defaults tab of the Manage Styles dialog box. When you are done, save and close Normal.

To display the dialog, click the Manage Styles button in the Styles pane (Ctrl+Alt+Shift+S).

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional