How to install El Capitan on a 1,1/2,1 Mac Pro

In my last article on how to flash the 1,1 Mac Pro to a 2,1 Mac Pro firmware I didn’t mention how to upgrade the operating system. The problem with the 1,1/2,1 (2006-2007) Mac Pro is that the latest officially supported operating system is Mac OS X 10.7 Lion. In this article I will explain how to put OS X 10.11 El Capitan on your 1,1/2,1 Mac Pro.

What you need:
• NVIDIA 8000 series graphics card or better.
The top graphics cards you can use are the NVIDIA 900 series or Maxwell Titan X.
Keep in mind that the use of a Maxwell NVIDIA card will require you to install and use their web drivers.
• ATI Radeon HD 2000 series graphics card or better.
The top graphics cards you can use are the AMD 200 series.
• A blank hard drive or partition available in your Mac Pro.
• RAM modules that are at least 2GB in size. 1GB or smaller RAM modules will cause issues.

First you will need to download the restore disk image of El Capitan (10.11.6) which you will need to install onto your hard drive of the 1,1/2.1 Mac Pro. To get the image click here. Now that you have the restore image it needs to be restored to your Mac Pro. There’s a few ways to go about this:
If you downloaded the image on your Mac Pro, use Disk Utility to restore it to the blank drive or partition you have reserved for El Capitan.
If you downloaded the image on another Mac, you can restore it to the Mac Pro’s empty drive or partition using Target Disk Mode.

If your Mac Pro currently has a functioning operating system on it, it is recommended you keep that drive/partition around as a fall back.
To restore the image to a drive or partition, do the following:

  1. Open up Disk Utility and click on the disk or partition you want to restore the El Capitan image to.
  2. Click ‘Restore’ in the top menu and select the image you downloaded in the ‘restore from’ box by clicking the image button on the right hand side.
  3. After you have selected the El Capitan image, click the restore button.
    This will take a while so you can go get a beverage of choice while this is happening. I suggest using an SSD as this will improve boot times on the Mac Pro once you are done.

Once the restore is done you can reboot the Mac Pro and hold down the Option key until you get the boot chooser screen. Pick the new copy of El Capitan you just restored and start up from it. That is all there is to it!

A couple of warnings once you have El Capitan running. It will say there are updates to install.
DO NOT INSTALL THE FOLLOWING UPDATE: “Security Update 2018-001” or any later Security Update, as this will break the installation and you will have to start over. The last security update you can safely install can be downloaded here. Once this is installed you can ignore all other security updates that apple throws at you. The best way to stop the nagging is to right click the update and click ‘ignore’. Other updates such as Safari etc. can be safely installed.

Thanks to Greg Hrutkay of Hrutkay Mods for the video on how to do this.

Thanks for reading and hope this helps you out.

27 thoughts on “How to install El Capitan on a 1,1/2,1 Mac Pro”

  1. Got a mac pro I flashed from 1,1 to 2,1

    4x4gb ram

    nvidia 8000 gpu (oem)

    applied your image and when I try to select the disk when holding option at boot, it just hangs at the disk selection screen forever.

    • Nic,

      Did you restore that image to your boot drive? You can’t just mount the image and boot from there. You have to use disk utility to restore that image. That is for El Cap only BTW. You can run ML on it with no problems.

  2. Nic,

    Did you restore that image to your boot drive? You can’t just mount the image and boot from there. You have to use disk utility to restore that image. That is for El Cap only BTW. You can run ML on it with no problems.

  3. Hello Greg,

    I’ve downloaded your image since my Mac Pro 1.1 doesn’t boot anymore (flashing folder with a question mark in it). I mounted the HDD (using an external enclosure) on a MacBook Pro with macOS Catalina. When I try to restore it as .dmg file I get the error “Could not validate source – Invalid argument” with OSStatus error 22.

    Anything I can try?

    • You have to restore it as an image not a dmg file. Just restore the image to the hard drive and it should boot. It will wipe the hard drive completely so any data on it will be lost.

  4. Hi Greg,
    If my mac pro’s os were already erased, yet it can not get into target disk mode. how can I install os on it?
    I tried making a bootable usb if they are installation application.
    with the dmg file, I don’t know how to make it into a bootable USB.
    Other than that, I tried cloning from ccc, another mac and time machine. Also internet recovery installed os doesn’t work for me.
    thank you for your help.

  5. Hi Greg,

    How does your system perform after the upgrades? Do you notice any issues using it online these days?

    Just found a 2x Quad 3ghz Mac Pro 1.1 flashed to 2.1 on a local classifieds. It’s running Lion 10.7 and 10.11 el Capitan. I need something for day to day online use and I’m looking for an ultra cheap solution.

    • I actually do not use the 1,1 anymore. I got a 4,1 and now use that one as a daily driver. You can find those pretty cheap now a days. I got mine for $150 so just keep looking and you will find a deal sooner or later.

      • I also use a 4,1 w/ last 4 versions of macOS on different boot volumes / drives as my daily work machine. So nice for us that these beautiful machines are so underappreciated. Looks like I’ll even be able to get Big Sur on it.

  6. Hi Greg,

    the link on Google Drive is not working, can you restore it?
    I take this opportunity to connect to Anna’s request, how can I restore with the operating system not present on the Mac, having only a Windows PC available?

    Thanks in advance

  7. Need help! Need hand walked basically. Flashed 1,1 to 2,1. Cheated and purchased El Cap from eBay. Started up first time and loaded. Now boot load screen takes forever and then shuts down when full loaded. No one can explain to me what is happening.

  8. Hi – any chance of someone re-uploading a copy of the El Capitan restore file? Or Tamarix, did you have any luck with another source?

  9. Im trying to create a bootable usb but all the tutorials that I’ve found requests the However, I’m using a Macbook Pro 2017 with Catalina on it, so I can’t install this app and get the .app file. Is there a way to extract .app from a .pkg?

  10. The problem I’ve had with the no later security updates starting with 2018 thing is because of it, no newer web drivers=no discord desktop capture in audio calls/voice chat. It simply crashes Discord attempting to do so which annoys me to hell.

  11. Hi,

    Thanks for the guide.

    I can boot into El Capitan and finished the setup. However My Macpro will restart few minutes everytime after login due to kernel panic. The message is “(cpu 2 caller 0xffffff801f4f6702): Invalid queue element pointers for 0xffffff8031de1e70: next 0….
    Anybody know what is happening?

  12. I flashed mac pro 1.1 to 2.1 -cpu Xeon X5365 (32 gb ram nvidia GT120-mac edition) and it works like a charm.I have one question? I found on web that El Capitan is the last mac os x that can run on mac pro 2.1.Is it true? Thank you.

  13. success

    need to report this. I downloaded the “el capitan.dmg above (using the later link paco 🙂 and restored it to a previously erased disk using GPT format onto the newly created volume.
    that worked and the system (macpro 2,1 dual 3GHz Xeon) booted into the post install setup which i completed.
    whoever tweaked that “el capitan.dmg” to boot 64bit on a 32bit EFI deserves a hands up. trust me, I tried all kind of approaches with refind and other, this is the only one that worked.

    – disable autoupdates, rather do manual. there’s one Update that will stop your mac from boting – duckduck which one
    – install Firefox 78.x well
    – install virtual box for other OS, avoid multiboot
    – my preinstalled GPU seems poor in performance, I will swap to a better one next

    thanks, the macpro 2,1 still performs very well


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