Hello AlexS,
Thank you for posting in Q&A forum.
Based on the description "I can't install to C:\Windows\policyDefinitions because it says", I understand you install it on Windows server 2022 and you receive the error message above.
Based on the error message, it seems you need to install all the latest update on server 2022, you can try to install all the latest updates by typing "check for update" on server 2022, after that you can try to install ADMX/L templates you mentioned above, and check it there is still error message.
You want to use GPO setting under Computer/Administrator Templates/Windows Components/Chat, you can also copy ADMX and ADML related to Chat from Windows 11 and paste to Windows server 2022, then check if you can see Computer/Administrator Templates/Windows Components/Chat in the GPMC on server 2022.
Hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou
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