File Explorer search not working in Windows 10 1909

After opening File Explorer try clicking on the View tab>Options>Change Folder and Search Options. Under the General tab>Open File Explorer to:, select Quick access then click Applyand OK and see if this allows you to use the Search Box. See image below, Click on, tap or activate image to enlarge it.

Also you may want to look at this.

https://www.tenforums.com/tutorials/94452-search-file-explorer-windows-10-a.html

I used the above.  It did not work - initially.  After a few minutes, it did.  I did check for updates afterward, but W10 said up to date.  I did not change anything from the default search settings.  Just re-applied the File Explorer search options to Quick Access.  I am using a custom theme, Dark Windows, Light Apps, Custom Color.  Build 1909.18363.592

Have you tried changing all of those settings, then restarting the machine, then and changing them back to your actual preference? I think what fixed it may have been changing all those visual settings at once, rather than changing them to a particular thing, causing Windows to essentially remake the visual of the file explorer window entirely. If it's that, it should fix anytime you change everything I did at once, and might stay fixed even if you change it back to your preference.

It's possible that making the initial changes to Personalization (Dark, etc., after installing 1909) broke search.  I have not changed them back.

Search works better now, since I performed the above Quick Access search config, which I re-posted above.

This problem seems to be related to indexing, perhaps slow indexing.  I do still occasionally have the issue return (can't click in the search box, etc.).  I have a lot of large files, including text files.  I'm also using Outlook 2016 with a large (1.5 GB) .pst file (Outlook is running, making frequent changes).  I am also running some other file intensive apps that access a lot of data.

Search works almost all the time now.  I can reliably get it to re-fail by opening a large text file in Notepad, making significant changes, saving, then trying to use Open... to search for a new text file to edit.  Closing and reopening Notepad fixes it.  So does opening a new instance of the File Explorer.

Updated to 1909 today - search feature does work basically Ok, one ore two hiccups. The big difference is the working thereof. Before, clicking in th search box brough up options as in Date, Name etc. Now these don't appear until you have actually entered something in the search box and done the search, then you can select option such as name etc. Then you have to re-enter your search again after 'name' appears, enter, and results appear although sometimes not exactly filtered. I was searching for a file, have a number of files where the first 2 words are the same but the 3rd varies, shows results for ALL files. By typing name in inverted commas, required file is only one listed as required. Also, intially, typing in an asterisk * brings up all files but also brings up search options such as date, name etc. Other small niggles. The old adage 'If it works - don't mend it' seems applcabe - something that was easy to do now requires a lot more input but does not always come up with expected results.

Have you tried changing all the visual settings also? I'm curious how the partial solution that doesn't involve the interface changes stacks with it.