Hi @Andreas Kalanidis ，
Sorry to hear that your issue has not been reloved now, have you tried the troubleshooting menthods as I mentioned before?
In order to further confirm if your issue is related to your search index , it's suggested to search via click "From" button like below to check if it could work normally.
It's you also couldn't work normally there, corrupted search index may cause it, if you haven't rebuild the search index, please try to rebuild it to check if the issue has any difference.
If you could search normally via the "from" button, it may be related to your language package, as I mentioned before, have you tried to switch to other windows display language to check(Start > Settings > Time & Language > Language.)? If not, it's suggested to change it or reinstall your language package for testing.
If your issue has any update, please feel free to post back :)
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