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!