I had some spyware and after removing it, the Windows search bar /F3/ become blank. I could not type anything to search.
This was a big trouble for me as I have thousands of files in my computer and search for filename or file content many times a day.
After researching the Microsoft page, I found this program: Tweak UI
It is a wellknown software. I have read many times about it but never used as I didn’t had need to tweak my Windows.
The program is small and easy to use.
Here is a screenshot:
Expand ‘Explorer’ then check ‘Use Classic Search in Explorer’ checkbox.
This solved my search problem.