Are there any cache's you can clear out for both?Edit:
I've never had this issue either, but I'm on Windows.
Did a little research, hopefully this can help you.
Photoshop - http://smallbusiness.chron.com/delete-photoshop-caches-44848.html
Why you're getting the error message for not enough memory:
"The reason for this is that Photoshop always creates a scratch file the instant you create a new file or open an existing document, and it estimates the needed size based on assumptions it makes as a result of your workflow history in the past. It does this for every open file."
They suggest that if you use photoshop for numerous files, that you try to aim for a 1TB harddrive because of that.
I can't find much of anything for Sai, but that's probably because it's not an English program.Unrelated, but that new name is bae.