I've been using photoshop CS5.1 for a long time now on MacOS Mojave 10.14.6.
After a couple of months not using, it now crashes as soon as I interact with it.ie it opens OK, I can even open a photo in RAW converter, but once I open in pjhotoshop, it crashes. I've tried the tric of systen preferences and changing how photoshop interacts with the computer, but it didn't wor. Any other ideas
I'm not a tech person, but my understanding is that with each updated newer OS, the old versions of Photoshop beccome more and more incompatible. CS5 is no longer supported by Adobe, either. It just might be time to go to Photoshop CC. There are various packages and programs you can buy, and if you just want Photoshop only, there's that too. You can find them here: Adobe Creative Cloud