Ok, you write But PS thinks my drive/s are full after I've been at it for a while. so I assume you disagree. I've seen many people who disagreed, but usually Photoshop is right. There's a simple test you need to do, because it changes completely the direction to go. When you get the message saying scratch disks are full, LEAVE THE MESSAGE ON SCREEN. While the message is on screen, leave Photoshop frozen and go back to Windows and check the free space on your five scratch disks. Maybe a screen shot from File Explorer would be interesting. (Clearly if you reply to the message Photoshop may release some space, that's why the message needs to still be on screen).
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