Photoshop 21.2 Masking problem

[Peter Carr]

When trying to do a simple mask, the screen display's black blocks. You cannot see what you are doing !!

[c.pfaffenbichler]

Please read this (in particular the section titled "Supply pertinent information for quicker answers"):

https://community.adobe.com/t5/Community-Help/Guidelines-Tips-for-the-Adobe-Forums/td-p/4788157

Does turning on (or off, depending on the current settings) Photoshop > Preferences > Performance > Legacy Compositing and restarting Photoshop have any bearing on the issue? 

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? 

[JJMack]

Can you post a screen capture it sounds like you may have a display adapter or device driver problem.

[Peter Carr]

Turning off etc. etc. doesn't help.

As soon as I use the Polygonal Lasso Tool, it does the following.

[c.pfaffenbichler]

Did you restart Photohop? 

Does hiding the Rulers make a difference? 

[Peter Carr]

Yes it looks like the rulers, THANKS !

Problem is I need to work with the rulers, especially with masking.

[Peter Carr]

Unfortunately, it's still happening without the rulers. Less frequent though.

[c.pfaffenbichler]

Then you may have to roll back to a Photoshop version in which the bugs were more manageable … not a great solution, I know. 

[Peter Carr]

Also happens with scrolling.

How do you roll back if it auto updates ?

[c.pfaffenbichler]

[Peter Carr]

Thanks.

Just for interest here's another screen shot.