My photoshop is virtual NOT USABLE

[SunflowerCreativeMedia]

I have had nothing but trouble with photoshop since I updated to 2021. parts of the photo would simply disappear but reappear when I zoomed in and out. I have upgraded my OS, I have uninstalled and reinstalled and it just gets worse. Sometimes I made a selection, and the selected area goes black. 

I have had my mac checked by Apple and they find nothing. Computer specs: Mac OS Big sur, 5K, 27inch Imac 2017, 64 gb ram, Radeon Pro 580 8 GB, 3.8GHZ Quad Core intel Core i5.

My laptop, which is older and a different graphics card works fine. 

Last night on the last photo I was processing (I'm a professional photographer) my photo opened above the area of view. as I scrolled down, the photo comes into the viewable window, but disappears as I scroll, so that only  about 1/8 of the photo appears, and I see the grey of the background color. I can't work this way! As I said before my laptop is fne, and I will have to use that for processing, but this should not be happening.  Is anyone else having problems, and is there anyway I can get help from adobe?

Thank you, 

Elaine

[c.pfaffenbichler]

Does turning off »Use Graphics Processor« in the Performance Preferences (Photoshop > Preferences > Performance > Graphic Processor Settings) and restarting Photoshop have any bearing on the issue? 

[SunflowerCreativeMedia]

No, I saw that written up months ago and tried it, it didn't help. On my first call to adobe, the advisor told me to go to full screen and it disappeared, so he told me, I had to stay in full screen. I'm just not used to that, I'm an old timer, whose been using photoshop and macs for over 20 years, and I didn't think I could do without the application frame, I called back and the advisor knew immediately what the problem was. Somehow my preferences were corrupted and when we eliminated them, it was fine. The advisor helped me to find my custom brushes and actions again, and my computer is running so much better in Photoshop! 

[c.pfaffenbichler]

https://helpx.adobe.com/photoshop/kb/basic-trouble-shooting-steps.html