Hey, you might have preset the background color while creating a new file:

Look at the section »Background contents«. Is the color set to white or something else?

You could try running the Creative Cloud Cleaner Tool to remove all traces of the Adobe software before reinstalling it (yet again):  https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html

Did you restart?

First, try disabling GPU in the Preferences (Performance tab). In Photoshop also go to Preferences > Technology Previews... and enable "Older GPU mode (pre 2016)" - Restart Photoshop. Any better? 

You can try this too: in Preferences>Technology Previews, check the box 'Deactivate Native Canvas' and uncheck 'Enable Native Canvas Rulers' options, then restart Photoshop. Does this work? 

If not, recalibrate and build a new ICC display profile, the old one might be corrupted.

If you are using software/hardware for this task, be sure the software is set to build a matrix not LUT profile, Version 2 not Version 4 profile.

If turning OFF GPU works, it's a GPU bug and you need to contact the manufacturer or find out if there's an updated driver for it. On the Mac, that's part of the OS update(s) so if this is the latest OS version, you may need to roll back a release. 

Also see: https://helpx.adobe.com/photoshop/kb/acr-gpu-faq.html

https://helpx.adobe.com/photoshop/kb/photoshop-cc-gpu-card-faq.html

Try the "Deactivate Native Canvas" options in preferences, and restart: is the green gone? 

Please help me with this problem. Your help is greatly appreciated!