Black Screen on Mac upon log in

Question

Black Screen on Mac upon log in

I'm getting a little disenchanted with Apple support and hoping someone out there has an answer. My problem is that for a single log on ID, my MacBook Pro screen goes black the moment I log in. I have an external Thunderbolt Display which works just fine as long as its set as the main display.

When I log in using an alternate log on ID, both monitors work fine so there must be a problem with that particular log in ID but only on the Mac Display. The problem with that though is my alternate User ID doesn't have any access to the data from the defective User ID (which is all of my data).

No problem if I could just restore my data to another user ID. I'd simply use the new ID and delete the damaged one. Problem is that I (nor so far Apple) knows of a way to restore data from Time Machine so that another User Id can use that data. Data always restores to the defective User ID so that alternate Users can't see the data.

I've wiped the HD and reinstalled the iOS (multiple times) and I've tried restoring the data a couple of different ways (as part of the process to reinstall the iOS and also using migration tool), but the data always restores to the defective ID.

I (and Apple) have run diagnostics and the only problem found is a weak battery in the Mac. No one seems to think that is causing the problem and if it was logic would suggest it would affect all User ID's.

Any ideas?

I will appreciate any and all suggestions.......

MacBook Pro 14″, macOS 14.7

Posted on Mar 28, 2025 10:05 AM

Reply

Answer 1

HWTech

Level 9

63,578 points

Mar 28, 2025 7:13 PM in response to Lone Star Gator

Have you tried booting into Safe Mode? If it is a software Login Items issue, then Safe Mode should allow you to log into that user account.

If it is a configuration/settings issue, then that is much harder to bypass or fix if you are not able to log into the troubled user accounts. The best way is to restore from a backup made prior to this issue occurring.

Reply

Answer 2

Mar 29, 2025 6:42 AM in response to Lone Star Gator

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.

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. 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 lower and settings ordinary. Use this as a starting point to customize settings to your liking.

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

• after 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

Reply

Answer 3

Mar 29, 2025 10:23 AM in response to Lone Star Gator

Ok, I have rebooted in safe mode. Results are identical. The moment I log into my usual (damaged) User ID, The Mac screen goes black. The external Thunderbolt monitor (which is set as main) remains functional. I can log into any alternate User ID (all of which are administrators) and both displays function normally. Same result when I reboot in normal mode.

One other thing I haven’t previously mentioned: if, when logged into the damaged User ID, i unplug the Thunderbolts display, the Mac display lights up looking like a blown out image with outlines of the expected image but with a purplish hue. Again though, when logged as any of my alternate Users, both monitors function perfectly.

One other thing I’ll add on the off chance it provides a clue: when logging in with my defective ID, a message flashes momentarily telling me the contrast is being increased. That does not occur when logging in with an alternate ID.

I appreciate your advice,,,, hoping for more ideas.

Reply

Answer 4

Mar 29, 2025 10:33 AM in response to Lone Star Gator

It seems there are 2 possible solutions: 1) repair the damaged User ID, 2) restore my Time Machine backup to an alternate User ID, then delete the damaged on. I have tried to restore to an alternate ID, but it always restores to the damaged ID such that alternate ID’s don’t have access.

Question: if I COPY (copy/paste - not using Time Machine) the contents of my HD to an external backup disk, then PASTE the contents of the external HD to back to the Mac using an alternate Log On ID, will that drop the permissions of the source data and grant permissions to the target (alternate) User ID?

Reply

Answer 5

Mar 29, 2025 10:53 AM in response to Lone Star Gator

<< the contrast is being increased. >.

then it is possible the issue is that the contrast setting has been 'slammed against the stops' for this user on this display.

Settings > Accessibility > Display ...

check the Contrast (and other) settings

Reply

Answer 6

Mar 29, 2025 11:51 AM in response to Lone Star Gator

Settings, Accessibility. display: Contrast was set 1 mark below mid point. Increase contrast was checked but makes no difference if I uncheck it. Intensity is set at midpoint.

Settings, Display: There is no contrast setting but brightness is at midpoint.

I assume that these settings are unique for each user? The information above is using the defective User ID. I haven't compared possible setting differences between users but I don't see anything on the defective User ID that leads me to believe there is anything to be seen?

Reply

Answer 7

Mar 29, 2025 4:14 PM in response to Lone Star Gator

increasing contrast off NONE is an accessibility function.

normally sighted people do not need to set it to anything but OFF.

on the other hand, brightness is a personal preference used daily. You can even control that with F1 and F2 on the keyboard.

those settings are unique for each user, for each display on each Mac you might be able to log in to.

Reply

Quick Links

Black Screen on Mac upon log in