When I was running 22631.2283 (KB5030219), everything was working fine. But after upgrading to 22631.2361 (KB5030310), the file explorer won't open anymore. Also shortcuts involving the explorer.exe, like ncpa.cpl, won't open anymore while shell shortcurts as sysdm.cpl do still work. When opening notepad.exe, i can do File -> Open and browse my drives, this is also still working.
But when opening explorer.exe directly, i get the following entry in the windows event viewer:
Have you possibly installed some sort of OS hack to regain older versions of Explorer or alter how the taskbar or explorer works?
I had disabled the Tabs in the Explorer via vivetool a while ago, but i have re-enabled them before upgrading to KB5030310. Just in case, i also ran sfc /scannow and dism /online /cleanup-image /restorehealth, but it didn't help.
For today, i'm using Explorer++ as a workaround. Tomorrow, i'll be doing an Inplace Upgrade of Win11 to try to get rid of this error.
I now understand that this isn't a Start11-related issue per se, but i'm not getting this problem on my other Win11 machines without Start11. It just happens on my main box with Start11, that's why i've posted it here.
/edit: Just before doing the Inplace Upgrade, i tried re-enabling the Tabs via vivetool again, and after a reboot, File Explorer is working again without any issues. Thank you for pointing me in the right direction. 
