Hi there, I have issues with Photoshop regarding the scratch disk preferences. It is not showing the accurate amount of storage for my SSD which is approximately 3TB of available space. Why is it showing the amount of my internal hard drive storage?
This happens often with MacOS and external drives. We see a lot of these posts.
First check that it's correctly formatted to APFS, and that all permissions are in order. The way this was once explained to me, Photoshop just reports the number it gets from the operating system. So you might want to ask in an Apple forum as well.
That said, a caution. Using external drives as scratch disk is not recommended. It will be slow, unreliable and not very efficient - and it may or may not work at all.
Secondly, you only have 22 GB free space on your system drive. That's a problem in its own right. I can fill up 22 GB in less than a minute, and then you risk the whole machine freezing up.
I would strongly recommend that you clear out space on your system drive. A basic configuration of operating system and a "standard" range of applications should not take up more than 90 - 120 GB. So even a small system drive like 500 GB should be possible to use as the primary scratch disk.