I have a 32 bit Windows 7 PC on which LR 5.7 has been installed since it came out about 2 years ago. For the past 2-3 months errors while using the Develop Module have been increasing. All are intermittent, but becoming more frequent. "Unknown error has occurred" - have to restart LR. (This is a really common one.) Masks for white and black stop working - have to restart LR. Crop - gray screen appears and nothing more happens - have to restart LR. Performance slows WAAAYYYY down - have to restart LR. It used to be only UNKNOWN ERROR HAS OCCURRED was the bug. Now these other errors have cropped up and I'm fearful this decline in performance is just going to worsen if I don't find a fix.
Any help? Please.
Try setting LR's preferences: http://www.lightroomforums.net/showthread.php?25197-Resetting-the-lightroom-preferences-fi le-updated . Sprinkling that magic pixie dust often fixes things when LR goes wonky.
Also, run a memory test. LR uses a lot of memory, and it's possible that you have a block of failing memory that only LR stumbles over (since it can use much more memory than the typical application).
You have some type of hardware problem. Could be RAM, probably, or the hard drive or your system is starting to overheat.
But is definitely a hardware fault.