Hi @Bobb ZHANG
Could you please let me know how did you uninstall Office 2021?
According to your description, this issue may be caused by Office 2021 not being completely uninstalled.
- I suggest you refer to the 'Option 2 - Completely uninstall Microsoft 365 with the uninstall support tool' in article 'Uninstall Office from a PC'.
- Then please restart your machine, install Office 2016 for a check.
If the uninstall support tool does not work, it's recommended to try following steps.
- Search CMD, right-click the Command Prompt and run as administrator. Then copy and paste the command below in it, click Enter at last:
cscript.exe "%ProgramFiles%\Microsoft Office\Office16\ospp.vbs" /dstatus
(If you are running 32-bit Office on a 64-bit operating system)
cscript.exe "%ProgramFiles(x86)%\Microsoft Office\Office16\ospp.vbs" /dstatus
- Then please share us with a screenshot of the command results or copy the results. I will check the Office license information.
- Please note, the commands needs to be run with Office installed.
Any updates, welcome to post back.
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