Adjusting the System Settings on an iMac without a screen

[SauropodWB]

I have an old iMac and the screen has died - there is no possibility to repair it as the spare parts are no longer available. I have a spare 21" monitor and would like to use it with this machine - here is my question: is it possible to configure Display settings to mirror the display without actually having a working display?

 

[MacsBug]

Depending on which iMac you have. I believe that if your iMac has a thunderbolt port in it, and your display has a display port you may be able to use a Mini Display Port to Display Port cable. Then when you start the iMac the 2nd display may work.

 

[SauropodWB]

Depending on which iMac you have. I believe that if your iMac has a thunderbolt port in it, and your display has a display port you may be able to use a Mini Display Port to Display Port cable. Then when you start the iMac the 2nd display may work.

Mine is a 2010 machine - so no Thunderbolt I'm afraid - but I do appreciate your response.

Regards,

Neil

 

[MacsBug]

Hi Neil,

The 2010 may not have a thunderbolt port, but it does have a mini display port which is what you need.

 

[SauropodWB]

Hi Neil,

The 2010 may not have a thunderbolt port, but it does have a mini display port which is what you need.

Hi,

I will purchase a mini-display port cable and give it a try

Thanks,

Neil

 

[JonathonPerry]

That’s a tricky situation with the dead iMac screen. If you can still remotely access your iMac, you might be able to adjust the display settings through Screen Sharing or a similar remote desktop tool. If not, you could try booting in Safe Mode and see if it automatically detects the external monitor. Otherwise, checking if an Apple store or certified technician has creative solutions for you might be worth checking.

 

[SauropodWB]

That’s a tricky situation with the dead iMac screen. If you can still remotely access your iMac, you might be able to adjust the display settings through Screen Sharing or a similar remote desktop tool. If not, you could try booting in Safe Mode and see if it automatically detects the external monitor. Otherwise, checking if an Apple store or certified technician has creative solutions for you might be worth checking.

Hopefully I will find out this weekend.

 

[SauropodWB]

I ordered a mini-display cable, once it arrived I connected it to my iMac and and an old monitor. Io my surprise both displays came on. Unfortunately the iMac appeared to be attempting to install Mac OS. It failed with the following message:
MAC OS could not be installed on your computer
An error occurred while loading the Installer resources.
Quit the installer to restart your computer and try again

I started the iMac in safe mode and was able to log in. Not knowing just how long the iMac display would hold out I went straight to System Settings in order to Mirror the displays. As I did this both displays distorted the. screen image such that I was unable to do anything - very difficult to explain how this appeared.
I hit the power button to reset the machine, but the machine no longer seems to recognise the shift key in order to start again in safe mode.
I don't know how to investigate why the machine is attempting an installation when I power it on. Does anyone have any ideas?

Thanks in advance,

Neil

 

[Rodananne]

Usually, when a Mac starts up and immediately attempts to instal macOS it's because the operating system (OS) is damaged. It may be that there is more wrong with the device that just the screen display. This could be hardware eg. the GPU or software. It may be that your screen is not dead but a symptom of a broader problem.