Since you can't open Photoshop, try the steps outlined in the correct answer on this discussion: Scratch disk full and cannot open photoshop to fix it... It's from 2013, but the info is still helpful. Another article that can also assist if you need to clear some space: How to Fix Photoshop Scratch Disk Full Errors
If that doesn't resolve the issue, can you let us know a little more information? What computer operating system are you using and what version of Photoshop CC? How much free space is available on your hard drive?
None of that worked , i have a macbook pro that i got two years ago.