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Macbook Pro 2016 not outputting to external display

Hello,

I have a Macbook pro 2016 I would like to connect to an external display. However, no matter what display (be it a monitor, projector or tv) or HDMI cable I try to use it does not display anything for more than five seconds before blinking once then failing.

MacOS Catalina is up to date.

I have tried Resetting PRAM and SMC with no success.

Booting In safe mode works but upon a restart out of safe mode it does not.

Using Bootcamp to run Windows 10 also works., so I doubt it would be my Thunderbolt 3 to HDMI adapter causing issues.

I have tried quitting all apps to no avail.

What further trouble shooting should I try?

Thank you, Luca

MacBook Pro 15", macOS 10.12

Posted on Mar 22, 2020 12:42 AM

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Question marked as Top-ranking reply

Posted on Mar 22, 2020 6:52 PM

Try creating a new admin user account. Log into the new account to see if the external display works properly. If it does, then you know the issue is due to something without your main user account. It could be a Login Item, an incorrect setting or a corrupt .plist preference file.

https://support.apple.com/guide/mac-help/set-up-other-users-on-your-mac-mtusr001/mac


If another user account behaves the same way, then you have a system wide software or settings issue. Run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper.

5 replies
Question marked as Top-ranking reply

Mar 22, 2020 6:52 PM in response to lucaQM

Try creating a new admin user account. Log into the new account to see if the external display works properly. If it does, then you know the issue is due to something without your main user account. It could be a Login Item, an incorrect setting or a corrupt .plist preference file.

https://support.apple.com/guide/mac-help/set-up-other-users-on-your-mac-mtusr001/mac


If another user account behaves the same way, then you have a system wide software or settings issue. Run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper.

Mar 23, 2020 7:12 PM in response to lucaQM

Double-check that the new admin user account does not have any login items set.


Safe Mode uses a more basic GPU driver. You could always try booting into Recovery Mode and reinstalling macOS overtop of itself. Even though this should not affect your data, you should still have a good working backup just in case. I'm not sure of the correct procedure to reinstall Catalina if you don't erase the whole physical drive since Catalina now has a read only system volume separate from the read+write user volume. I've never had to reinstall Catalina overtop of itself. This is the only Apple article I can find about installing Catalina and it does not mention anything specific about the new disk layout. Maybe the installer is smart enough to figure things out automatically when reinstalling overtop of itself.

https://support.apple.com/en-us/HT201475


Otherwise the most likely cause is one of the other apps running at startup. The next most likely culprits which would have ties to the display would be EA Origin and Steam.


It is also possible this could be a hardware issue. It wouldn't hurt to run the Apple Diagnostic. A passing diagnostic result doesn't really mean anything, but if the diagnostic reports a problem then that may be significant. The only sure way to eliminate software issues is by performing a clean install of macOS by erasing the whole physical drive and reinstalling macOS without migrating or restoring from a backup. If issues exist with a clean install, then you will need to contact Apple directly since it either indicates a hardware failure or a macOS issue.


To erase the physical drive while in Recovery Mode you will need to click on "View" within Disk Utility and select "Show All Devices" before the physical drive appears in the left pane of Disk Utility. The drive should be identified something like "Apple SSD ....". Erase the physical drive as GUID partition and APFS (top option). After erasing the physical drive select "Reinstall macOS".


Make sure to backup your system first.

Mar 23, 2020 4:17 PM in response to lucaQM

The most likely culprit would be XQuartz since it deals with X Windows and the display. Make sure it is completely up to date. If it is at the latest version, then try uninstalling it by following the developer's instructions.


I would suggest uninstalling the AppCleaner app by following the developer's instructions. Cleaning apps are not needed on macOS and they usually cause more problems than they solve. They also impact system performance.


Macbook Pro 2016 not outputting to external display

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