Could not use the brush tool because the scratch disks are full.

adobe photoshop CC 19.0

Macbook Air OS X El Capitan 10.11.6

I am getting tired of these. So I just solved a problem regarding illustrator awhile ago and then now I have this: "Could not use the brush tool because the scratch disks are full."

How can I get pass this problem now??!

Ever since the update, things got wild. These things take a lot of my time and it's interrupting my workflow and it's getting very very frustrating.

Any help is GREATLY appreciated.

Marco