
Please check which version of Office for Mac you are using.
Where are the Word documents stored?
If the changed content cannot be saved, you can copy it to OneNote or other software first. Then try following steps to check this issue.
1.Clean the Word cache folder.
Quit Word app from dock bar and then open Finder > press Command + Shift + G > input ~/Library/Containers, remove Microsoft Word(or com.microsoft.Word in Catalina) folder to desktop.
2.Run Mac in Safe Mode.
This can help us to exclude any possible influences from other third-party apps or background programs that may have a conflict with the Excel app.
See: How to use a "clean startup" to determine whether background programs are interfering with Office for Mac and kindly refer to the Apple article in the last one to get detailed steps.
3.Reinstall Word to the latest version.
Go to the Applications folder and drag Microsoft Word.app to the trash. Then restart your Mac, download the latest version of Word from: Update history for Office for Mac - Office release notes.
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