You were likely given bad advice about your disk requirements. Photoshop needs plenty of disk space when processing large files (as well as being a large application). Your way out of this (assuming you don't want to replace your Mac) is to get a fast external disk to offload much of your internal disk.I just deleted about 50GB worth today because Photoshop wouldn't open because of lack of disk space. I guess this is my new part time job, deleting these stupid files. I only have a 256GB drive so this is pretty annoying.