I’ve the same problem too.
I used my Sandisk Cruizer Edge (32Gb) on Windows 7 x64 and Mac Os X 10.7.x for a long time, but from some days I’m unable to add, change or delete files on both OS. I’ve checked on the Disk Management (under Windows) and I’ve noticed that the flash-pen is “Read Only” but I’m unable to change that status.
I can’t format it, because I receive the error “The disk is write protected”… so, now I’m trying to change files status (I see that “Archive” is checked), but again in some files I receive the same error…
It’s very weird… even because I’m able to read everything on it… so the flash-pen works… I’ve tried to disable and unistall it, but again, when Windows recognize it, present the same error…
Tried even with SecureAccess but nothing… I’m unhappy 
