MP 1,1-5,1 Mountain Lion Installer Fails on Mac Pro 5,1

[quadra605]

I have a 2009 Mac Pro 4,1 with firmware updated to 5,1. I use it to run older software I still need. I've created a USB boot installer for Mountain Lion 10.8.5, but I keep getting a message that it couldn't complete the purchase & isn't compatible with my computer.

I've tried disconnecting from the internet & changing the date back to 2013 when ML was released but no luck. I managed to install Snow Leopard without any issues, so I'm not sure what is preventing ML from installing. Any ideas?

Thanks!

 

[Dayo]

You might have an old installer from when the version was still sold but you can now download this from Apple without payment. Use this script I wrote to create a bootable USB:

Creates Bootable USB for Mac OS Lion to Monterey (Excluding Mavericks)

Creates Bootable USB for Mac OS Lion to Monterey (Excluding Mavericks) - Install_USB_Maker.sh

gist.github.com

Instructions, including how to get Mountain Lion, are the top of the script.
The script might be broken for HiSierra and newer but recently used for Lion to LoSierra (Excluding Mavericks).

 

[Macschrauber]

I have a 2009 Mac Pro 4,1 with firmware updated to 5,1. I use it to run older software I still need. I've created a USB boot installer for Mountain Lion 10.8.5, but I keep getting a message that it couldn't complete the purchase & isn't compatible with my computer.

I've tried disconnecting from the internet & changing the date back to 2013 when ML was released but no luck. I managed to install Snow Leopard without any issues, so I'm not sure what is preventing ML from installing. Any ideas?

Thanks!

If you have the Polaris GPU (Radeon RX4/5) then this could be the issue. Plug the original GPU back in for installing.

 

[quadra605]

You might have an old installer from when the version was still sold but you can now download this from Apple without payment. Use this script I wrote to create a bootable USB:

Creates Bootable USB for Mac OS Lion to Monterey (Excluding Mavericks)

Creates Bootable USB for Mac OS Lion to Monterey (Excluding Mavericks) - Install_USB_Maker.sh

gist.github.com

Instructions, including how to get Mountain Lion, are the top of the script.
The script might be broken for HiSierra and newer but recently used for Lion to LoSierra (Excluding Mavericks).

Thanks! The link you referenced in your script is where I downloaded my ML installer from. I read through your instructions & I think this is a just little over my head. I assume this terminal command is the critical part:
Execute "chmod +x /Path/to/this/script/file" without quotes and then run this script file

So the script file is the "Install_USB_Maker.sh" file I get when I unzip the download, correct? After executing the chmod command, how do I actually "run" this script?

 

[Nermal]

cd /wherever/the/script/is
chmod +x Install_USB_Maker.sh
./Install_USB_Maker.sh

 

[quadra605]

You might have an old installer from when the version was still sold but you can now download this from Apple without payment. Use this script I wrote to create a bootable USB:

Creates Bootable USB for Mac OS Lion to Monterey (Excluding Mavericks)

Creates Bootable USB for Mac OS Lion to Monterey (Excluding Mavericks) - Install_USB_Maker.sh

gist.github.com

Instructions, including how to get Mountain Lion, are the top of the script.
The script might be broken for HiSierra and newer but recently used for Lion to LoSierra (Excluding Mavericks).

I successfully created the usb boot installer for Mountain Lion with your script, but once the computer booted up & I tried to install, I still got a message that my computer was not compatible, and it only offered my the option of restoring from a time machine backup (which I don't have). I tried disconnecting from the internet and turning back the clock to 2015, but that didn't help. Not sure what else I should try--if anyone has any ideas, I'm open to them!

 

[h9826790]

I successfully created the usb boot installer for Mountain Lion with your script, but once the computer booted up & I tried to install, I still got a message that my computer was not compatible, and it only offered my the option of restoring from a time machine backup (which I don't have). I tried disconnecting from the internet and turning back the clock to 2015, but that didn't help. Not sure what else I should try--if anyone has any ideas, I'm open to them!

View attachment 2323055

Is that a generic 10.8.5. Or a special version of 10.8.5 for a specific Mac restoration?

 

[Dayo]

I still got a message that my computer was not compatible

Not sure of the provenance of the installer you used but I have used the version from this Apple Support Page:

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com

Specific link to Mountain Lion on that page is: https://updates.cdn-apple.com/2021/...1A65-42DD-BBEA-E1D9F43A6B3F/InstallMacOSX.dmg

You mount the InstallMacOSX.dmg file from that link and not any other file you might have, run the script and use the USB Installer created.

If you do that and still get the stated outcome, then Apple might have changed something or there is something different from a normal MP51 with your unit/setup. There should be no need to disconnect from the web or change dates etc btw.

PS: I hope you are not trying to install while booted via OpenCore spoofing some unsupported unit

 

[quadra605]

Not sure of the provenance of the installer you used but I have used the version from this Apple Support Page:

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com

Specific link to Mountain Lion on that page is: https://updates.cdn-apple.com/2021/...1A65-42DD-BBEA-E1D9F43A6B3F/InstallMacOSX.dmg

You mount the InstallMacOSX.dmg file from that link and not any other file you might have, run the script and use the USB Installer created.

If you do that and still get the stated outcome, then Apple might have changed something or there is something different from a normal MP51 with your unit/setup. There should be no need to disconnect from the web or change dates etc btw.

PS: I hope you are not trying to install while booted via OpenCore spoofing some unsupported unit

Yes, I was using an installer from that link, but no luck. I did find an old HD from my 2010 MacBook Pro that had ML on it, so I ended up just cloning that drive onto my MacPro. Not the best workaround, I'll admit, as I still don't know why the install didn't work. But I was pressed for time working on a project that needed to access an old version of software that no longer runs on my current OS.