MacBook Pro (2017) external display only works in Safe Mode

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MacBook Pro (2017) external display only works in Safe Mode

I'm having an issue with my MacBook Pro. It's from 2017 and runs on Intel core.

A year ago the screen of the device stopped working and since then I have been using it connected to an external monitor rather than replace the laptop or fix the screen.

However, yesterday the MacBook stopped connecting to the screen unless I'm in safety mode.

I believe the issue might have been caused by a Microsoft auto update I accidentally agreed to.

I'm completely stumped on how to fix this. I have gotten rid of lots of apps and checked for anything using high CPU percentage. I've also checked for daemons and log in add ons which might be affecting it but still no luck.

I have ofc deleted Microsoft auto updater and anything related to that. I have also reinstalled the Monterey OS but no joy.

A techy friend of mine advised that it is likely a driver issue if it works in safe mode and recommend uninstalling or reinstalling the display or graphic drivers. But he doesn't us Mac.

Any help would be greatly appreciated!!

Thanks you for reading all of this 🥰

MacBook Pro 15″, macOS 12.7

Posted on May 6, 2026 3:23 AM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

143,591 points

May 6, 2026 6:15 AM in response to Mikeyhello

Safe Mode is also the key to getting a display set to out0of0bounds settings back into kinetic.

Safe Mode does a number of different things.

On older Intel Macs, hold shift at startup, but have your userid and password at the ready.

On newer Apple silicon Macs, shut down your Mac. Then as you start up again, hold the power key until the ’Startup Options’ screen appears.

A parade of unusual things happens.

• Your Mac loads just enough of the kernel to do a disk check. Then it proceeds to do a disk check and if needed, make Repairs. This can take an extra about five minutes.

• your userid and password are required, even if you normally auto-login. So have them handy.

• Your Mac adds ONLY a minimal set of Apple-Only extensions, Not including graphics acceleration extensions. Screen updates will therefore be wonky and slow, but it ultimately should be correct.

• Your Mac assumes defaults for as many settings as possible, including screen resolution.

This is the key for re-setting the screen, but there is a little more to it: Resolution is likely to be temporarily lower and settings ordinary. Use this as a starting point to customize settings to your liking.

If you make NO changes, regular mode will just revert to what you had set before, so DO make changes!

Any changes you make in Safe Mode will "stick" in regular mode after you restart.

• after a Restart in normal mode, your Mac will take slightly longer to start up [once] because it rebuilds some system caches.

"Works in Safe mode, fails in regular mode" implies "It's something you added".

How to use Safe Mode on your Mac

Start up your Mac in safe mode - Apple Support

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