Masks not masking out whole area

[Christina24359678o99w]

I am attaching picture of what is happening. I want the photo masked in an octogon and the mask is exactly correct in the layers panel.  But the photo is not masked correctly on the main screen.  I have done this about 20 different ways trying to figure out what is wrong and can't fix it.  I have mostly figured out photoshop myself so am a trial and error kind of user with lots of online videos to supplement as needed.  I cannot find an answer for this issue.  Please help!

Thank you!

Christina

[Christina24359678o99w]

Here is a photo with the background off which better shows what I was talking about.

[barbara_a]

It could be a GPU issue. 

[barbara_a]

Take a look at GPU settings in Preferences > Performance.

[D Fosse · Accepted solution]

Agree with Barbara, this is most likely GPU-related.

You can try to disable the GPU completely, just to quickly confirm. But I'd be curious to see if this exported correctly, IOW just an incorrect screen representation. If so, try to check this:

If applicable, there's also the "older GPU mode" checkbox below it.

If you post the contents of Help > System Info, that might give a clue to the underlying problem.

[Christina24359678o99w]

When I opened Photoshop today my image was correctly cropped on the home page but still wrong on the main screen.  My GPU was not checked in preferences.  So I deactivated the native canvas and turned on the GPU, restarted Photoshop and now everything is correct!  I had exported the photo from Lightroom but I do that all the time with no problems so I am not sure if that had anything to do with it.  Thank you all for your help!