Search problems after upgrading to windows 10 20H2

I upgraded to this update yesterday (from windows updates), it was available automatically. But after upgrading, I faced this problem:

Whenever I start typing in start menu, search doesn't appear.

When I click on search bar, then type something, no results (in fact nothing) appear and search closes automatically after few seconds.

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Update: I fixed this issue myself; I just opened the reliability monitor from Control panel and found that "ConstraintIndex.Search.dll" was causing the problem, so I googled and found that I just had to delete this key from the registry:

"HKEY\_CURRENT\_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Search",

I am not sure what exactly it does but it fixed the issue.