Upgrading legacy Mac pro 3,1 to MacOS High Sierra success story

My Mac Pro from before 2010 was happily running MacOS Mavericks I think. There were some minor annoyances, but mostly it was working pretty swell. And a couple of years ago the machine dropped from the supported hardware list of newer MacOS releases like Sierra and High Sierra. So no more official software upgrades then.

Just recently I stumbled upon the the website of Collin Mistr (http://dosdude1.com/highsierra/) providing unofficial installer patches for Sierra and High Sierra to support select legacy hardware models including the Mac Pro 3,1.

Although I was somewhat worried to try something as well, unsupported, on an otherwise perfectly stable machine, I was to curious not to try.

So I followed the steps provided on the link above and was running High Sierra in just a couple of hours of waiting. All in all the time investment was under an hour. Swell! The only thing not supported seems to be the Wifi adapter which I do not use anyway. Gigabit ethernet FTW.

During the process there were just to minor problems :

  • After downloading the images on my MacBook Pro, the tool complained about being unable to mount the High Sierra installer. A reboot of the laptop fixed that one.
  • The Mac Pro is running with an encrypted disk. The High Sierra installer supports this, but the patch software that Collin wrote did not expect an encrypted volume. I fixed this by running the High Sierra installer again up to the point where you select / unlock the target disk. After that I restarted the patch utility and it was able to patch my system drive just fine.

As this is a great way to extend the life of this ‘ancient’ machine and it all was a smooth ride, the PayPal account was used to show my love for Collin and his work. Thanks!