Re: I'm using a Mac running OS 10.9.5, with Photoshop CS5. When I try to update PS, everything downloads, and when it's done I get the message "There was an error downloading this update. Please quit and try again later." Not sure what's going on.

Delete all data from following location on your machine and try updating again.

Mac OS: ~/Library/Application Support/Adobe/AAMUpdater/1.0/

Let me know if it works for you.

Regards,

Ashutosh