Here is a quick tip we got from photographer and soundman extraordinaire Matthew Monroe. If Photoshop on your Mac is running slow, or worse, giving you the “scratch disks are full” message, there are things you can do.
Let’s talk about scratch disks for a second: scratch disk is where Photoshop stores information which is too big to store in RAM. This can happen when working with big files, applying complex filters and other instances where your RAM is just not big enough. If you have not made any changes to your default Photoshop installation, there is a good chance that your scratch disk is also your system disc (which is also your documents disc).
The smaller the scratch disk is, the slower Photoshop will run. And if it’s small enough, you will get the infamous “scratch disks are full” error.
Luckily the solution is easy, or at least the immediate front line support. Just free some space on your disk. For Matt, it was the downloads folder which was hogging over 12 GB of disc space.
Here is the incident as Matt describes it:
Quick tech tip if your computer seems to be running a bit low on memory: check your downloads folder.
My MacBook Air had been giving me “low scratch disk” warnings for the past week, and I just couldn’t figure out what was sucking up memory.
And then I decided to open up my downloads folder.
And –– oh my!–– it was a complete and total horror show of base .dmg files (i.e.: compressed installer programs and applications).
Soooooooo… I spent a good fifteen minutes going through and deleting all .dmg files and –– next thing you know –– I opened up 12 GB of memory.
I’m happy. My computer’s happy. Most importantly, Photoshop (which is a huge memory hog) is super happy.
And if you start clearing out that downloads folder, the chances are good you’ll be happy, too.
There are more ways to clear disc memory, like removing temp files, deleting caches and more, you can look here for some ideas.
A long-term solution would be to get a dedicated scratch disc or to use a fast external disc for working on your documents while freeing some space on the main drive.