I'm using ACR 5 on a Mac 10.5.8. I have 279 raw files in a folder. I selected all in bridge, command R, and only 16 photos will open in raw. What could cause this?
Limited memory? Limited ACR scratch disk space? Go into the ACR preferences and give yourself a healthy amount of ACR cache, say 10gb or more.
Quitting and restarting ACR helped...but it happened again. I increased the cache in preferences as you suggested...problem solved! Thank you!