I sometimes copy large files in internal memory, such as nands, with Root Explorer, and then paste them to my sd card.

It takes a while to perform the operation and so I am patient with it. i haven't tried to do anything with the phone in the meantime, I don't know if it would respond in such a case as it would be sort of busy.

Is that what is happening with you?

 

I'm not really big on the AOSP roms, so I'm not 100% sure. I think there were some issues with accessing the storage on CM10 early on in development, but I'm not % sure.

I'd suggest breaking the number of files you transfer at one time down, might be trying to force 10lbs of stuff into a 5lb bag too fast and it breaks it.

Also I like your suggestion of flashing back to a stock or sense based rom to check to see if it's just CM10. Make a nandroid backup and flash a sense rom, try it again. Post back what happens.

 

I'm running Pac man which is AOSP and I have no trouble what so ever with the phone freezing when copying files. I have copied several ROMS over to the internal storage drive (ISD) most sense ROMS run about 600 megs or so. I have had no trouble accessing and coping these files to ISD. I would try to do a fresh install of another AOSP ROM and see if the issue comes up again. If it does you could have a problem with your ISD.

 

Also check for funky cable.