Please provide your full system info, and especially the video display sub-system specs..
It might not hurt to post the specs. of a typical file, that is causing this too.
Last, please post a screen-cap, or list the Crop Tool's Options.
I think that's a pretty good indication of a display driver problem.
Assuming you have a PC, visit the web site of the maker of your video card, download and install their latest release for your hardware and OS. Video driver updates solve many problems.
Thanks so far.
I think with you all this might be a PC issue, but still not sure. Point is that CS6 crashes often CS5 is not. I can even reproduce a crash using the NIK Color Effex plugin, detail extractor. It gives me a 100% crash. I also tried to reproduce the same with CS5 and all works fine.
So on 1 side this could be because of the PC demands of CS6, on the other hand it could be something in CS6 itself.
I did however tested earlier the use of Videocard acceleration (turned it of). Maybe indeed it was better, but unsure yet. My video drivers are all updated (latest version)
Yesterday i got un update from Adobe but have not tested this yet in full.
So i'm not done testing yet, but in the meentime reinstalled CS5 with all the plugins again.
My PC configuration is:
Intel i7 3.2Ghz
32 GB mem
Video: AMD Radeon HD 6900
Win 7 64bit
This should be sufficient by far to work with Adobe without any problem.
PS: it seems also NIK is updating software. So maybe crashes and cropping tool will be solved by the software itself. I'll keep this topic updated.