Unable to install or update to Mojave on Optiplex 990 running High Sierra

[rcohen04]

successfully installed High Sierra on OptiPlex 990 in Legacy mode. I have trouble figuring out UEFI mode, and adding a BOOT source properly, so Legacy mode seems to working just fine.

Compiled Hackintosh version of Mojave as directed by guide for new drive, and also tried installing from Native Mac OS installer over the High Sierra install, but error message received. "Unable to install - corrupt installer. I've tried downloading the Mac Os Mojave installer on several different computers, but I think the error message here is coming from compatibility of the OptiPlex 990.

Clearly there is some hurdle I'm missing - perhaps a patch or a BIOS setting, but I've tried switching a few things without any success.

Anyone have suggestion?

As a newbie, I'm not familiar with troubleshooting but would appreciate any guidance to get Mojave or Catalina installed.

 

[trs96]

would appreciate any guidance to get Mojave or Catalina installed.

Your 1050 GPU is not supported past High Sierra.

 

[rcohen04]

Your 1050 GPU is not supported past High Sierra.

I’ll check the model but I know I’m using a PCI card with an ATI graphics card. Would that cause the installer to be recognized as unable to move forward or corrupt? Sorry it’s an AMD

AMD RADEON MODEL C552 HD-8570 GRAPHIC CARD​

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