We have recently received the same feedback from many users and this has become a hot issue recently. After our investigation, your problem should be caused by an error in the account information recorded by the Office application, at this time I would recommend that you clean up the account information in the registry and then reopen the Office application and log in. Below are the exact steps:
1. Press Windows + R to open the run box, copy and paste the following path, back up all the folders in this path, and then delete them.
%localappdata%/Microsoft/OneAuth
%localappdata%/Microsoft/IdentityCache
2. Press Windows + R, enter regedit, click OK, open the registry, locate the following registry subkey, right-click Identity, and delete it.
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\Identity
Disclaimer: In general, changing registry subkeys or workgroup is intended for advanced users, administrators, and IT professionals. It can help fix some issues, but serious problems can arise if you modify the registry incorrectly. Therefore, make sure to follow these steps carefully. For additional protection, back up the registry before editing it. Then, you can restore the registry if a problem occurs. For more information on how to back up and restore the registry, click How to back up and restore the registry in Windows - Microsoft Support to view the article.
If the problem reappears after cleaning the registration information, please refer to the following method to roll back Office applications to an older version:
1. Please close all Office applications first.
2.Run Command Prompt as an administrator ("Win" logo key + "Q", enter "cmd", select "Run as administrator"), and enter the following commands one by one.
cd %programfiles% \Common Files\microsoft shared\ClickToRun
Officec2rclient.exe /update user updatetoversion=16.0.17531.20120
3. After completing the installation, please restart your computer, then open the Office application and sign in to your Microsoft account.
4. Please open any Word/Excel/PPT document > Click on File in the upper left corner of the page > Click on Account in the lower left corner of the page > On the right side of the page, there will be information about your Office product, please click on the update option on the left side of the Office Update > In the menu, find the Disable Update, to avoid the problem of updating Office to the latest version. to prevent Office from updating to the latest version and causing the problem again.