Display issue since trying to install Monterey

[Sans Souci]

I wonder if anyone can help me, my friends MacBook Air needed a refresh so he reinstalled the OS from recovery partition which took it back to Yosemite (it’s an early 2015 MacBook Air). He was unable to access internet via Safari (able to access internet via other apps including App Store). My thoughts were that with Yosemite being an older OS it may not be ‘up to date’ enough so suggested we create a USB install disk for a newer OS version which was compatible with that model year (Monterey was the chosen OS).

We inserted the USB stick, booted the laptop while holding the option key and got the option to boot and install from the USB monterey image which we chose. As the process progressed the screen changed to grainy verticle lines which we’ve been unable to move on from.
we’ve tried booting while holding option command P and R with no success and tried booting into safe mode without success.

Does anyone have any other ideas which may help please?

 

[rovostrov]

I wonder if anyone can help me, my friends MacBook Air needed a refresh so he reinstalled the OS from recovery partition which took it back to Yosemite (it’s an early 2015 MacBook Air). He was unable to access internet via Safari (able to access internet via other apps including App Store). My thoughts were that with Yosemite being an older OS it may not be ‘up to date’ enough so suggested we create a USB install disk for a newer OS version which was compatible with that model year (Monterey was the chosen OS).

We inserted the USB stick, booted the laptop while holding the option key and got the option to boot and install from the USB monterey image which we chose. As the process progressed the screen changed to grainy verticle lines which we’ve been unable to move on from.
we’ve tried booting while holding option command P and R with no success and tried booting into safe mode without success.

Does anyone have any other ideas which may help please?

This could be because the display is failing. First I would try a SMC and PRAM reset, then try booting into safe mode to see if that fixes the issue. If not, try connecting to an external monitor. If the air works with the external monitor, you will probably need to replace the airs display.

 

[Sans Souci]

I’ve tried PRAM reset and SMC reset — I plugged into an external monitor but didn’t get any output at all?

 

[rovostrov]

I’ve tried PRAM reset and SMC reset — I plugged into an external monitor but didn’t get any output at all?

Maybe try safe boot? If that doesn't work, perhaps try reinstalling the OS. If all of that fails, I'm out of ideas. Hope you get it back up and running.

 

[Audit13]

Open the MacBook and try reseating the video cable.