Trying to delete Studio 2021 Freelance prior to reinstalling. I get the following error message:

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Trados Studio 2021 SR2
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Setup did not complete. The error is:
Setup has detected a different version of this product already installed. If you still wish to remove or repair that version, you must use that version's installer.
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OK
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Cannot get any further! 

I can neither delete nor reinstall Studio.

I am trying to reinstall after the following error message started to appear when trying to open projects:

Unexpected exception when initializing Part Fragment Matches.