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Use Mountain Lion in VMware Fusion with Tools

Note: As of VMWare Fusion 4.1.2, this hack is no longer necessary. I've left it here mainly for those using older versions of Fusion (though you may not be able to install newer Mountain Lion previews on those older versions of Fusion).

If you're a Mac developer with access to OS X Mountain Lion, you might want to use it in a virtual machine. This is simple in VMware Fusion, but if you try to install VMWare Tools, Mountain Lion will kernel panic. Unfortunately, using virtual OS X without VMware Tools installed is painful—no screen resize, captured and laggy mouse, etc. So here's a workaround to get Mountain Lion working with VMware Tools (this assumes you have Mountain Lion already running in a virtual machine):

  1. Make a snapshot of your current setup!
  2. Run the VMWare Tools installer, but do not reboot when it's done. Just leave the installer running onscreen.
  3. Navigate to /Library > Application Support > VMware Tools.
  4. Delete vmmemctl.kext and vmmemctl
  5. Edit (you'll need root power) in that same directory.
  6. Comment out these two lines (they're shown commented out, via the # in front of each):

  7. Save the edited file, quit the editor, and now (via the still-running Installer) reboot the virtual machine.

The initial reboot may take a long time, but it should work. If it doesn't, you're on your own, as I've now exhausted all my knowledge on the topic.

39 thoughts on “Use Mountain Lion in VMware Fusion with Tools”

  1. I did a bit of digging, and spoke with some friends who know lots about virtualization. Please let me know if it works; I did one other thing that I didn't think was required, so didn't include it here. If it turns out it doesn't work for you, I'll have to add it and hope that's the missing bit.


  2. Rob it works as far as I can tell, thanks a lot. The curser seems kinda glitchy but that might be the way it is.

  3. I already installed the tools and then rebooted and got a kernel panic that wouldn't go away, so I found your post too late. It was still helpful, though. Here's what I did.

    1. Boot into single user mode by rebooting the VM and quickly giving focus to the screen and holding Command-S. If you don't do this quick enough, you'll miss the window of opportunity.

    2. Once you get the root prompt, type: /sbin/mount -uw /
    to mount the drive with write permissions

    3. cd to /Library/Application Support/VMWare Tools

    4. Delete the files you mention and then edit the file using vi and make the changes you noted.

    I was able to get it to boot and the tools seem to be working correctly.


  4. @Matt Long - this can actually be done easier with just holding the Shift key down during the boot, and going into Safe Boot mode. ;)

  5. osx 10.8 runs in 32bit kernel mode also..

    macpro:~ hany$ uname -a
    Darwin macpro.local 12.0.0 Darwin Kernel Version 12.0.0: Mon Jan 30 18:40:46 PST 2012; root:xnu-2050.1.12~1/RELEASE_I386 i386

    Tools are ok, thank you Rob :)

  6. Works great, many thanks Rob!

    Do you need to delete the kext and script even though you commented out the startup lines in

  7. @David. Set the machine in full screen before reboot and direct click after that followed with Command S. You will se direct the single user load mode.

    @Matt Super - you saved my day here.

  8. If you don't load it you don't need to unload it...

    In the line that unloads vmmemctl.kext should also be commented out.

    If you have not already become accustomed to VI and have no intention to memorize VI commands then use nano for these quick tasks. Is easier to pick up and included in the OS.

    I followed your instructions and was able to boot into ML after the tools install.

  9. Can someone explain step 5 in a bit more detail? When I try to edit in text edit, it says it's locked and it makes a duplicate somewhere else instead of changing the original. If I open in the Console instead of text edit, I can look at the code but I don't see a way to edit it.

    He says you need "root power" to edit it. I've changed the permissions of the file, and I'm administrator, but I still don't see how to edit Any help?

    tl;dr Can't edit; how do I get root power?

    1. Tanner:

      The easiest way to do this is to download BareBones' free TextWrangler; it should be able to edit the file as it exists, saving when you provide your admin password. (I _think_ that's how it works; it's been a long time since I tried it.)


  10. Raul Rodriguez Abad

    Excelente trabajo Rob!!! ha sido super util... Estaba a punto de abandonar hasta que encontre la informacion en tu Blog... Muchisimas gracias!!!

  11. Hello,
    i just installed preview 3 and did this suggested tweak. now whenever i recycle mountain Lion i get a garbled login screen. it wont let me even login.

    any suggestions


    1. With Fusion 4.1.2, you shouldn't need this tweak. With that said, I can't imagine that the tweak would have any impact on a garbled login screen: I occasionally get that even in 10.7 and 10.6 virtual machines. The fix is to use the menu to change the screen mode to/from full screen and single window; that usually solves the problem for me.


  12. The garbled login screen was fixed for me by turning the 3d acceleration on in the VM settings.

    (Unsing VMWare Fusion 4.1.3)

  13. Upgraded a virtual 10.7.4 to 10.8 FINAL and run into kernel panic … Started in Single User Mode, deleted the files (vmmemctl.kext and vmmemctl) and outcommented the two lines inside and - IT WORKS. :)

    Great guide!

  14. I am not sure if this thread is still relevant, but I was able to successfully run OSX 10.8 in VMFusion 4.1.3 with host version OSX 10.7.4 by performing these steps:

    Matt Long Says:
    February 16th, 2012 at 4:11 pm
    I already installed the tools and then rebooted and got a kernel panic that wouldn’t go away, so I found your post too late. It was still helpful, though. Here’s what I did.

    1. Boot into single user mode by rebooting the VM and quickly giving focus to the screen and holding Command-S. If you don’t do this quick enough, you’ll miss the window of opportunity.

    2. Once you get the root prompt, type: /sbin/mount -uw /
    to mount the drive with write permissions

    3. cd to /Library/Application Support/VMWare Tools

    --- I stopped at step 3 as I was not able to successfully edit the .sh file. I rebooted the OSX 10.8 VM and after performing a force restart from VM Fusion I was able to succesfuly launch my 10.8 machine and run the VMWare Tools through the VM Fusion menu. The OSX 10.8 VM is working correctly.

    Good luck!

  15. Thanks for this!

    I had a loop of kernel panic on startup. Before this, I had Fusion 4.x and upgraded to Fusion 5.x. And then when I upgraded from Lion to Mountain Lion in my VM, the VM would no longer boot because of the kernel panics. I believe the issue was that I had not updated the VMWare Tools when I'd updated Fusion earlier.

    So, I booted to single user mode and disabled the memory kext as described. That allowed me to boot. Then I was able to install the Fusion 5 VMWare Tools and reboot and all is well since.

  16. I think this work for everyone, but me. I deleted the 2 files used sudo su - in termail to edit the .sh file saved and rebooted with panics. I'm on vmware 9 in ubuntu. Van't get a fix to work. ARG!

  17. Thank you.
    I was advised to go here by SoulDev.
    I was getting kernel panics after installing Vmware tools on Mountain Lion on Vmware Workstation 9.02.
    Followed your guide and this time, no kernel panics :)
    So I can confirm it works on the Windows Vmware Workstation too.

  18. I can't quite to get this to work. I use AMD E-350 though with an AMD kernel, so that may be the issue. Does anyone have any advice?

  19. Thanks a lot! This really helped!

    @ Jesse: I got this working on an AMD E-350 with VMWare Workstation 9.0.2 and OS X 10.8.3 without a problem using souldevteam's AMD pre-patched OS version and using their VMWare Workstation AMD unlocker.

  20. I can't seem to locate:
    /Library > Application Support > VMware Tools.

    it says folder not found :[. Please help me! Thank You

  21. Having the same problem as the above user, cannot find;

    Library > Application Support > VMware Tools

    The folder is empty even though I installed it correctly.

    Any ideas?

  22. When I go to the Application Support folder, I cannot find the VMWare Tools folder, it simply isn't there.

    I installed VMWare Tools but didn't click the restart button just like the guide says.

    I'm Using VMware workstation 10 and the tools from osx ML 10.8.3.

    Any ideas?

  23. Sorry I can't be of any help; I stopped using 4.x long ago, and haven't looked at it in well over a year. Everything I know on the subjects is contained in the post.


  24. thanks rob, i just figured it out. Im a noob, which is why I was having trouble. For all the noobs out there like me, just keep working at it until you get it. I have a 1055t and I finally got it to work on win 7 64 VM Workstation after many days of trying. I guess the moral of story is to: NEVER GIVE UP!! Thanks to rob and all of you for your kind support!

  25. Ugh. Still can't get this crap to work properly, I get a kernel panic. Not even worth the time and effort anymore this was my last try

  26. Just want to say thank you so much for this post. I was pulling all my hair out trying to setup this virtual machine but it kept hanging at the boot screen after installing VMWare Tools. You are god.

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