I believe I'm still having the originally-reported issue... I'm running Start10 1.55, and have tried uninstalling, rebooting and re-installing... when Windows 10 pushed out the latest big update, it seemed to alter (kill) the ability of Start10's search to find control panel and programs... it searches a lot of files, but is definitely not finding fundamental things that it used to.
My most frequent use of it is to type "windows upd" to pull up Windows Update... when I do that now, all that comes up is "Find and Fix Windows Update Problems" under a Control Panel heading, nothing else. When I do that under the normal Windows Start menu, it immediately pulls up Windows Update Settings as the top result.
I'm not sure when this first started happening, as I've been going through some other computer issues, also related to this recent windows update - but I think I'm seeing what is reported here. I'll keep searching the forums and googling, but figured I'd ask if there's something I should check within Start10. I did turn off "Search should include files outside the standard libraries" and then turn it back on again, that didn't seem to have any effect.