UniBeast: Install OS X Mountain Lion on Any Supported Intel-based PC


Staff member
Nov 18, 2009
i5 10600K
Vega 56
  1. MacBook Air
Classic Mac
  1. Apple
  2. PowerBook
Mobile Phone
  1. iOS
Installing or updating to the latest version of OS X on a PC is simpler than ever. This guide requires no programming or coding experience and all of the tools are available right here on

UniBeast Overview
1. Purchase the OS X Mountain Lion Application from the Mac App Store
2. Prepare a UniBeast USB flash drive
3. Install OS X Mountain Lion
4. Install the bootloader and drivers using MultiBeast

In order to start fresh, you'll need access to a functional computer running Mac OS X Snow Leopard 10.6.6 or later. This is a requirement, as you need OS X to create the installation drive. To start from scratch, booting the 10.6 Snow Leopard Retail DVD directly, check out iBoot + MultiBeast. For a quick rundown of recommended BIOS settings, check out this post.

You Will Need

8GB or Larger USB Flash Drive
Amazon Newegg

Install OS X Mountain Lion
Mac App Store

STEP 1: Purchase OS X Mountain Lion
The operating system is not free. Purchase and download the Application from the Mac App Store using an Apple ID on any Mac or functional computer running OS X 10.6.6 or later.

STEP 2: Create a Bootable USB Drive Using UniBeast
Take a deep breath and take your time- this is pretty simple, but it's easy to miss things if you rush. Follow each step to the letter.

1. Insert the USB drive into a USB 2.0 port
2. Open /Applications/Utilities/Disk Utility
3. Highlight the USB drive in left column​
4. Click on the Partition tab
5. Click Current and choose 1 Partition
6. Click Options...
7. Choose Master Boot Record
8. Under Name: type USB (You can rename it later)
9. Under Format: choose Mac OS Extended (Journaled)
10. Click Apply then Partition
11. Download and run the latest version of UniBeast
12. Click Continue, Continue, Continue, Agree
13. At Destination Select, choose USB and click Continue
14. Choose Mac App Store Mountain Lion - 10.8
15. (Optional) If using a Socket 1156 system without Rate Matching Hub (RMH) USB choose Legacy USB Support
16. (Optional) If using a laptop, choose Laptop Support
17. Click Continue
18. Enter password and click Install
The process will only take about 10-15 minutes, depending on system and drive speed, but may show hours. This is normal. Do not unplug or stop during this time.​

STEP 3: Install OS X Mountain Lion
You're almost done! All you need to do is boot from the USB drive and install! Set your BIOS or UEFI to Optimized Defaults, and your hard drive to AHCI mode.

1. Turn on the computer
2. Press the hotkey to choose boot device​
  • If you have a Gigabyte motherboard press F12
  • If you have a ASUS motherboard, press F8
3. Choose USB-HDD

4. At the Chimera Boot Screen, choose USB and hit Enter

Optional Boot Arguments & Troubleshooting Tips
For some hardware, it may be more difficult to get to the installation screen. For maximum compatibility, we recommend using integrated graphics (HD 3000/4000) for the installation, then adding your discrete graphics card after a successful installation.

You may have to type extra boot arguments in the system at the boot screen you see above. You can hit arrow-down as well on the boot screen to access boot options. Here are a list of things you can try in order to troubleshoot booting to the installer. You will have to troubleshoot this part yourself according to your own hardware specs. We've provided a few tips below.

Black Screen, White Screen, Flickering Screen
It's your graphics or possibly your choice of graphics port. The DVI or the HDMI port are usually the most compatible for installation. Reboot and try another port or one of the following flags.

This setting may be necessary on motherboards using Fermi and Kepler NVIDIA cards for installation.

UniBeast has PCIRootUID=1 set by default for the most universal support for recommended builds. Set it manually to 0 by typing this command at the boot screen above.

You can install without graphics card injection. This can solve many issues, allowing you to access the installer screen.

Verbose Mode- allowing you to see the loading of the OS instead of the Apple Boot Screen.

Safe Mode- loads only basic drivers. Sometimes a cure-all to reach the installer.

Special Instructions for AMD 6xxx Graphics Cards:
There is an issue with AMD 6xxx cards in Mountain Lion. We recommend using an alternate graphics card or onboard Intel HD 3000/4000 graphics for the entire process. After you're fully installed, you can switch back to your 6xxx card.

5. When you arrive at the Installer, choose language.
6. For a new installation of OS X, you MUST format the destination drive according to the following steps before continuing.​
NOTE: If you are upgrading from Snow Leopard or Lion and you want to keep your files and apps, you can skip steps a-j.

a. In the top menu bar choose Utilities, and open Disk Utility
b. Highlight your target hard drive for the Mountain Lion installation in left column.
c. Click Partition tab
d. Click Current and choose 1 Partition
e. Click Options...
f. Choose GUID Partition Method
g. Under Name: type Mountain Lion (You can rename it later)
h. Under Format: choose Mac OS Extended (Journaled)
i. Click Apply then Partition
j. Close Disk Utility
7. When the installer asks you where to install, choose Mountain Lion, or your existing install.
8. Upon completion, restart the system.

STEP 4: Post-Installation Using MultiBeast
MultiBeast is an all-in-one post-installation tool designed to enable boot from hard drive, and install support for Audio, Network, and Graphics. In addition it includes System Utilities to repair permissions and a collection of drivers and config files. The installation is complete, but the drive isn't bootable yet. Boot from the USB again, this time choosing Mountain Lion.

1. Turn on the computer
2. Press the hotkey to choose boot device
  • If you have a Gigabyte motherboard press F12
  • If you have a ASUS motherboard, press F8
3. Choose USB-HDD
4. At the Chimera Boot Screen, choose your new Mountain Lion installation.
5. Complete Mac OS X Mountain Lion setup.
6. When you arrive at the desktop, open Safari
7. You should have working Ethernet from UniBeast, or if you have a native Wi-Fi card.
8. Browse to and log in. If you don't have a user account, create one!
9. Visit to download the latest MultiBeast
10. Visit the DSDT Database to download your motherboard's DSDT

NOTE: Gigabyte UEFI motherboards don't require a DSDT.

11. Open the Downloads folder and move the .aml file to the Desktop
12. Open and run Multibeast's UserDSDT or DSDT-Free Installation and any further drivers to enable audio, network, graphics, etc...​

UserDSDT Installation for a CustoMac build using Realtek ALC 889 and Realtek Ethernet

DSDT-Free Installation for Ivy Bridge/Haswell CustoMac using Realtek ALC 898 and Intel Ethernet

Yay! You now have a fully updated bootable version of OS X Mountain Lion on your CustoMac! And a handy USB rescue drive to boot from in case things go pear-shaped. It's easy to get frustrated, but don't give up! If you get stuck, there are many users with similar hardware in the tonymacx86 Forum to provide support. Special thanks to everyone in the community, and our Mods for testing!

If you've had success using this guide, consider a contribution to help keep the sites going. We're constantly updating and tweaking our tools to help you. Good luck and have fun!​

UniBeast 10.7 Lion Guide
iBoot + MultiBeast - 10.6 Snow Leopard Guide
Quick guide to configuring the UEFI on Gigabyte's 7-series LGA-1155 motherboards


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Last edited by a moderator:
Jul 16, 2010
Asus Pro WS x299 Sage II
RX 5500 XT
  1. Mac Pro
Mobile Phone
  1. iOS
Once Unibeast was completed everything working great. I noticed that unibeast timeline(progress bar) is screwed up though. Not just 1.5.3 but older versions to. No big deal for me as it completes the installation to USB but some people may think its stuck or not longer responding.
Nov 8, 2011
Classic Mac
Mobile Phone
But still not happy i have to use a Mac to make a bootable Lion drive @@
Dec 21, 2011
i5 - 2500k
Geforce GTX 260
Classic Mac
Mobile Phone
  1. iOS
upgraded my lion to mountain lion with no problem at all, just followed your guide using unibeast then multibeast... just reinstalled applehd kext... but there is no dvd player and when i launch dvd player apps it gives me this message "There was an initialization error A valid DVD drive could not be found. [-70012]". in lion it's ok dvd is working fine. tried fresh install but it is still the same...
Sep 12, 2011
motherboard or system make & model # > See Rules!
Nvidia > need model # > See Rules!
  1. MacBook Pro
Mobile Phone
  1. iOS
Great job on the upgraded ML guide. I bought the GA-UP4 TH and installed ML with previous version of Multibeast. Is there a screen shot of which options to use for that board to get it functioning optimally and with USB 3 enabled? It's my first time installing using Tonymac method. My previous GA-UD5 I followed another guide from another website. Excited by the potential of this board. Any help is greatly appreciated! Thanks in advance :)
Aug 17, 2011
MSI p67a-g43
Radeon 6950 1GB
  1. MacBook Pro
Classic Mac
Mobile Phone
  1. iOS
Article: UniBeast: Install OS X Mountain Lion on Any Supported Intel-based PC

Mobo: MSI P67a-G43
CPU: 2500K
Video Card: AMD Radeon 6950 1GB
HD for OS X: OCZ Agility 2
OS X Version: Lion

So, I created a UniBeast USB stick, booted into it, used Disk Utility to partition and format my 60GB SSD to the Mac partition type (Journaled or whatever it is). Did the install.

Now, when I boot from the UniBeast and choose my Mac OS X installation, it just goes to a gray screen with a black mouse cursor.

A few things: When I installed, I left all my drives plugged in and also have 16GB of RAM (I never removed it so there is only 4GB). I'm not getting any errors returned to the screen.

So what are my next steps?
Dec 1, 2010
Classic Mac
Mobile Phone
I'm running a GA-H55M-S2V with a i3 540, and MSI N8400GS-D512H graphics. I tried to perform an update to my 10.7.4 machine, and have no problem installing ML using UniBeast 1.5.3. However, when I try to boot into the ML updated drive using UniBeast, I am getting a hang at [PCI Configuration Begin].

I tried the NPCI=0x3000 boot flag, but this caused the boot to hang 2 lines earlier than before. I then booted into my backup 10.7.4 lion instance and ran MultiBeast 5.0.2 against the 10.8 instance, but this didn't seem to help either. I used the appropriate DSDT when running MultiBeast, but I am not sure whether or not running MultiBeast against a drive that you are currently not booted into is a supported/recommended use of MB. I figured it couldn't hurt to try.

I should point out that I selected "Legacy USB Support" in UniBeast, as my MB is a Socket 1156. I couldn't find the way to determine if my MB had a rate matching hub, and so I erred on the side of caution.

Any ideas on what I should try next in order to be able to boot into 10.8? Prior to ML, I haven't had a single install issue with this machine, since 10.6.3 (if memory serves, that was the my first hackintosh OS nearly 2 years ago).

Thanks very much!
Mar 9, 2011
My own hand-picked parts
Core i7 2066K
HD 6870 by Gigabyte
Classic Mac
Mobile Phone
I currently have Lion with a rig of Gigabyte HD6870 with 2600K on GA-P67A-UD4, and the MB doesn't have output for integrated graphics...any ideas how I'm going to get through with the HD6xxx advice and install?
Jul 24, 2012
gigabyte z68-ds3
core i7-2700k
geforce gtx 470
Classic Mac
Mobile Phone
Article: UniBeast: Install OS X Mountain Lion on Any Supported Intel-based PC

Thanks to allTONYmans! You do greatest things!:clap: