Scratch Disk Full, But I cannot change my Drive?

Did you try swapping the disks? It is strange the D is on 0 while c is on 1...

Based on the responses we can only speculate as to the cause. I would try to start with a new drive install. Based on your drives you are in desperate need on a clean drive. Another option may be to invest in an external USB drive. However, in looking at the current prices not a real good deal ar present. The 8TB SATA can be has ~$110 USD

The OP did already clear them. I'm really puzzled.

Photoshop AFAIK keeps a list of unusable scratch disks. Try resetting preferences

When it worked, were the drives already  inverted? Wondering as well about the boot sections.

I recently saw someone with a problem that they got the scratch disk warning when only one was full.

I have seen Windows apps fail to write to drives. This is primarily thumb drives requiring a special format. More concerning is the drive space remaining on your C drive. A possible cause may be PS is reading the lack of space on all drives? Minimum space for PS install is ~8 Gb. Although there appears to be headroom, there may be some reserve space in this area? Depending on the age of your computer I would seriously consider purchase a new SSD. In order to insure you do not loose your data on the C drive take it off line. Next step is to develop a backup strategy. You can pickup an Internal SATA drive for ~$100 USD.

And heres some information that shows what you were looking for.

As previously mentioned this is a definite issue caused by Photoshop and not Windows, Every other Adobe App recognises everything, I've tried resetting my preferences and even reinstall Photoshop on the latest version, No success. One extra thing I did was even download Photoshop on my D drive! And it installed and runs prefect! It's on the drive I want to change it to and yet it STILL cant recognise it!!!

Right, So I freed up a ton of space on both drives, yet I still need to configurate my Photoshop onto my D drive. This used to be recognized by photoshop and yes its an internal drive windows recognises it perfectly fine. One way I can let you know that this is definitely a photoshop issue is due to the fact that Illustrator fuctions perfectly fine and recognises BOTH drives.

Make sure the drive/partition you want to use as the scratch disk shows Healthy.

If you are comfortable troubleshooting in Windows you can follow the link below. If not once in Disk Management take a screen shot and post. Will guide you from there.

https://learn.microsoft.com/en-us/troubleshoot/windows-server/backup-and-storage/troubleshoot-disk-management