I'm running Windows 7 and Photoshop CS5. I've been using the program with ACR 6.0 for about 2 weeks with no problems. I installed AC 6.1 Release Candidate tonight and opened a Canon raw file from a 7D. I did all of my adjustments in Camera Raw and then opened the file in photoshop. When I try to save the file the program goes into a loop and hangs up, basically locking photoshop up and making me have to shut down the computer to reboot it. After the reboot, I went back into the same file again with the same results.