I am having this same issue. Doesn't matter what I am searching for and it isn't 100% of the time (but close to it) but almost always, when I type into the "search programs and files" box it will start trying to search and within a second or two explorer.exe will crash/restart. I have not seen this behavior at any other time besides when I try to search using Start11 "search programs and files" box. I am running version 2.08 (release).
The install is a fresh install of Windows 11 with a fresh install of Start11. No upgrading.
EDIT: POSSIBLE SOLUTION?!
After lots of internet searching on the issue and fiddling, nothing seemed to help at all. EVERY time I used Start11 search, Explorer restarted, so I gave up on it. While I had the Start11 settings window open I disabled the "Show settings in the taskbar clock" which doesn't take effect until after Explorer restarts (no problem getting that to happen of course! I tested search again and boom Explorer.exe restarted/crashed as usual only now it wasn't showing the seconds on the clock...and now it seems Explorer.exe is not crashing on searches. 
This MAY be coincidental as Start11 search does not ALWAYS cause crashes in Explorer.exe, though the vast majority of time it does. It did however stop immediately after disabling the "show seconds in taskbar clock" option and then restarting Explorer.exe (That setting specifically states it does not take effect until Explorer is restarted.) I will keep an eye out on it and report if I still have further Explorer crashes with Start11 but with a little blind luck I may have stumbled onto a fix for the issue (that will hopefully help others with the issue as well).
