Why is there a dark vignette around the edges of my Mac's screen?

"Why is there a dark vignette around the edges of my Mac's screen?"

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Thank you for the photo.

Troubleshooting Lines on a Mac Screen:

It may be a hardware error, or it may not be. Before deeming that is the case, try a few things...

A. Use to Correct Power Adapter:

Are you using an Apple brand power adapter? If so, make sure it is the correct one to user: Identify your Mac Power Adapter - Apple Support

B. Restart your Mac:

Restart you Mac, and see if you still get this issue.

C. Try Safe Mode:

In Safe Mode, login items do not run, and corrupt system files(i.e. caches) are intentionally reset as a way to fix issues.

1. Boot: in to Safe Mode
2. Log in: as same user
3. Wait: 30 seconds
4. Restart; your Mac
5. Log in: as same user
6. Open: [the app]
7. See fi the issue persists.

D. Single-Out this User:

For troubleshooting purposes, create an Administrator user, seeing if you do not get this occur while in it. If so, then it is an issue with the configuration of the current user. If not, then it is an issue with the entire Mac, in which case you should get it serviced. See below...