Made any changes to the OS lately?
I am working with Windows 7. NO changes made!
Try turning off the GPU in LR / Perfs / Performance. Switch to the Library module first. LR 6/CC uses the GPU by default since it helps speed up 4K displays, but there are video card drivers that aren’t compatible and this can cause lockups.
Unfortunatly the switch off of the GPU doesn't work either. Some how a sub routine "shadow" does lock up the system.
Any other suggestions?
Be aware I am not a computer wizzard!