Although at this stage I've got well used to Windows 8.1 due to it being on my workplace PC, one thing that does bug me is the inability to kill explorer.exe when it's not responding. In this instance, it seems to be a bug in OneDrive for Business where it stops responding in the middle of a file copy/move operation:
As the above first screenshot shows, it gives 'Restart' instead of 'End Task'. Clicking 'Restart' does nothing in this instance as it just seems to sit there waiting for it to gracefully close. If I try forcing it to close in the 'Details' tab, it tells me 'Access is denied'!
Basically, I have no problem killing the Explorer.exe process when it's responding fine (which I just tried), but if it's not responding, it sure puts up a fuss. It's the same even with an Administrator command prompt where ID '4732' here is the explorer.exe process:
I don't recall ever having trouble killing explorer.exe in Windows 7, whereas in Windows 8.1, it requires restarting the computer. So far explorer.exe hasn't hung yet on me in the few days I've been using Windows 10.