Hi dougn, CS3 is an very old application and Sierra 10.12.5 is the latest version, so there are compatibility issues are possible as CS versions are not tested on new operating systems.So it might or might not work. As you said you were able to install and work on it and its giving issues while saving files. Please try following steps. 1) Boot system to safe boot with same account and check how it works, if it works fine close all third party running services. For details click here Use safe mode to isolate issues with your Mac - Apple Support 2) Log in to root account For details check here How to enable the root user on your Mac - Apple Support Check how application works there, If it works fine Go to Location ~/Library/Preferences right click preferences folder and click get info Click the lock icon to unlock it, then enter an administrator name and password. Change permissions to read and write. Click the Action pop-up menu , then choose “Apply to enclosed items.” If you do not see your account there click on plus symbol on bottom left corner and add account and follow same steps Follow same steps for ~/Library/Caches ~/Library/Application support /Library/Preferences /Library/Caches /Library/Application support Note: If you are on office system ,these (/Library/Application support and/Library/Preferences) folders may or may not allow you to add user , that is completely fine. Then reboot the system back to normal account and check performance. Regards Srishti
... View more