Scratch disk is full issue & cannot export date

[Nichelle5C55]

After updating Photoshop, I've received "scratch disk full message" after trying to use every tool, I've cleared all of the cache, and I have more than enough storage on hard drive (only been using this laptop for 2 months). Also, when finally ready to export after deleting every file on my Mac  Big Sur, I get a "unknown error message". 

[Test Screen Name]

How much EXACTLY is this "more than enough" you have on your hard drive?

[Nichelle5C55]

30 GB on the "free space" on the Photoshop> Preference >Scratch Disk> Macintosh HD. Which I read scratch disk automatically takes 6 GB. So 24. 

And 207 GB out of 245 on overall Mac Storage

***I plugged my external hard drive and that has 3 terabytes available ***

[Test Screen Name]

" I read scratch disk automatically takes 6 GB. So 24. "  I don't know where you read that. 30 GB is not enough. Please try this.

1. Start Photoshop, run until you get the "scratch disk full" message.

2. LEAVE THAT MESSAGE ON SCREEN

3. Go to About this Mac and get the storage page

4. Check if the disk is now full - or post a screen shot.

***I plugged my external hard drive and that has 3 terabytes available ***

That's a good amount but did you tell Photoshop to use that drive instead? It will NOT do that automatically.