Most weird monitor issue with Catalina

[NMM303]

Hi all

I'd love to pick ya brains.

When I plug my MacBook Air to my 27' Dell monitor via HMDI I get this weird looking thing on my monitor screen. It won't go full screen when I put my Mac into clamshell mode.

I can't do anything with the machine other than to restart.

Any ideas guys? It's so bizarre.

 

[Taz Mangus]

Try a SMC reset.

Reset the SMC of your Mac - Apple Support

The SMC is responsible for managing power on your Mac. Resetting it can resolve certain uncommon issues related to power or thermal management.

support.apple.com

 

[NMM303]

Yep - tried both the SMC and NVAM reset but to no avail.

Might have to clean install Catalina?

 

[Taz Mangus]

Yep - tried both the SMC and NVAM reset but to no avail.

Might have to clean install Catalina?

Try booting into Recovery Mode and install the latest Catalina version. This will install the full version of Catalina. Maybe this will refresh the system files.

The other thing maybe try is create a clean new user. Disconnect the monitor, create a new clean user, logout of you account, login to the new user and connect the monitor.

The next thing to try is booting into Safe Mode and see if the issue still happens.

If all those don’t work then maybe consider doing a erase and install from Recovery Mode.

 

[NMM303]

We're nearly there! The new user trick WORKED. Full screen every time. Then switched back to my admin login, no ball. It's broken.

There must be something very wrong my user (as administrator)

What would you suggest I do now? How can I transfer all my current apps and data to new user log in?

 

[Taz Mangus]

We're nearly there! The new user trick WORKED. Full screen every time. Then switched back to my admin login, no ball. It's broken.

There must be something very wrong my user (as administrator)

What would you suggest I do now? How can I transfer all my current apps and data to new user log in?

Try removing everything you are start running in your user account such as Login Items. Then look at remove everything in your Library/LaunchAgents folder. Then restart the computer. If that works, start adding back in items to see what might be causing the issue.

 

[NMM303]

Try removing everything you are start running in your user account such as Login Items. Then look at remove everything in your Library/LaunchAgents folder. Then restart the computer. If that works, start adding back in items to see what might be causing the issue.

Thanks Taz - no dice with this one.

I'm guessing the final solution here is an erase and install etc..?