Hello there,
This can be caused by a trivial problem like the language settings of your system. Corrupted or problematic drivers can also produce this issue so make sure you update them.
Use this CMD to check your system language
DISM /online /get-intl
You can’t keep Windows settings, personal files, and apps message appears during Windows 2012 setup when the language from your previous operating system doesn’t match the one on your Windows 2019 ISO file.
You can also check this article for the insight https://answers.microsoft.com/en-us/windows/forum/all/the-keep-personal-files-and-apps-option-is-greyed/6f918306-d8c4-4890-8671-ade4780d6bb8
Hope this resolves your Query !!
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