Got the same Issue.
Windows 10 & latest Defraggler.
I started defragging my HDD, then clicked on another drive and it froze.
Now I cant see the progress it makes or cancel it. Very annoying.
Seems like this wasnt a problem in earlier versions.... might switch back then
Seems like delivering Crappy / worse updates is becoming a trend recently
Just created this account so I can let you know this is still an Error.