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A Mac machine needs to be reformatted with Lion. I backed up the Lion dmg file when I purchased it via the Mac App Store.

I now need to create a bootable USB drive from the DMG file but I need to be able to do it in Windows, preferring open source or at least free options.

How can I do this?

3
63

Use TransMac, which has a 15-day trial period and works flawlessly.

  1. In the left pane, right click the USB Drive and select Format Disk for Mac

  2. In the left pane, right click the USB Drive and select Restore with Disk Image

  3. Point to your .dmg (or choose All Files to select an .iso) file and click Open.

enter image description here

It will take a few minutes depending on size of .dmg and speed of USB drive, but once done you can pop it into your mac, hold down the option key when turning on the mac and choose the USB drive.

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  • 1
    Awesome application, thank you. It helped me to create a Mac Recovery USB. My friend created this Recovery USB and made a DMG file using Disk Utility and sent it to me over internet. Then using TransMac I burned DMG on my USB stick and was able to recover my macbook from failure – Dmitriy Jun 29 '14 at 18:03
  • Is it compatible with El Capitan, etc? – 101 Sep 16 '16 at 1:45
  • @101 Not sure, but I suspect it should be. – Eric B. Sep 16 '16 at 1:47
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    Also after these steps in TransMac first Format Disk For Mac, then restore disk image – RegencySoftware Apr 13 '17 at 22:49
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    Is it normal that it takes approx 5h to create the drive? (I have a Lexar 2.0 8GB) – Tanckom Mar 10 '20 at 1:06
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TransMac worked for me, but first you need to partition your USB drive with GPT. It will not work if partitioned as MBR. diskpart on Windows can do this:

diskpart
DISKPART> list disk
(Find the disk number)
DISKPART> select disk 2
Disk 2 is now the selected disk.
DISKPART> clean
DiskPart succeeded in cleaning the disk.
DISKPART> convert gpt
DiskPart successfully converted the selected disk to GPT format.
DISKPART> create partition primary
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    I think this should have been included as an edit or comment to Eric B.'s answer. – StockB Aug 24 '15 at 11:36
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    This did NOT work for me. I got a prohibition sign when attempting to boot from a USB created through transmac with the GPT. I followed the procedure precisely. I had to use Carbon Copy Cloner to get past that. superuser.com/questions/1052037/… – stackOverFlew Mar 27 '16 at 22:00
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    Also after these steps in TransMac first Format Disk For Mac, then restore disk image – RegencySoftware Apr 13 '17 at 22:49
  • Personally, since Mac is so fussy, I'd rather use the tool designed to do this job, aka TransMac can format to GPT vs using DiskPart, but always good to know alternate methods – FreeSoftwareServers Jan 18 '18 at 6:26
6

As far as I know, the only way to properly create a bootable Lion disc/disk is to use Disk Utility on a working Mac. However, the other option is to use a Virtualbox VM to run OS X temporarily (scroll down for that info).

On a Mac

The guide from lifehacker:

  1. Download Lion from the Mac App Store. The installer should show up in your Applications folder.

  2. Right-click on the installer and hit "Show Package Contents". Navigate to Contents > SharedSupport and look for a file called "InstallESD.dmg".

  3. Open up Disk Utility and drag the DMG file into the left-hand sidebar. If you're burning it to a DVD, insert your DVD, select the disk image in the sidebar, and hit the "Burn" button. Skip down to the last step to use it.

  4. If you want to burn Lion to a USB flash drive, plug it in and click on it in the left-hand sidebar in Disk Utility. Go to the Partition tab and select "1 Partition" from the dropdown menu. Choose "Mac OS Extended (Journaled) on the left.

  5. Hit the Options button under the partition table and choose "GUID Partition Table". You'll need this to make the drive bootable on a Mac. Hit the Apply button when you're done to format your drive (note: it will erase everything on the drive).

  6. Click on the "Restore" tab, choose the InstallESD.dmg file as the source and your flash drive as the destination. Hit the Apply button and it will create your bootable USB drive.

  7. Reboot into OS X and hold the option key when you hear the startup chime. You can boot into your DVD or flash drive from there.

On a PC

I know this works with Snow Leopard, but I'm not sure about booting Lion in Virtualbox. My suggestion is:

  1. Acquire a Snow Leopard iso image

  2. Use this guide to convert the Lion dmg into an iso

  3. On Virtualbox click "New"

  4. Choose OS as Mac OS X and click on 64bit or 32 bit (depending on your system) Snow Leopard

  5. Choose VDI as storage and click next

  6. Click on Dynamically Allocated space

  7. Give 4096 MB of Ram for optimum performance or you can also give 2048

  8. Once finished click on the Virtual OS you just created and click on settings.

  9. Go to storage and click on the disk below the vdi storage.

  10. Click on the empty disk button on the right side of the window.

  11. Choose the .iso file you converted earlier.

  12. Just click ok and start the Virtual OS

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Necromancing.

I couldn't get it to work with TransMac.
TransMac couldn't read the dmg images.
It said 0 bytes, and finished in sub-second speed.

However, this is what worked:

  1. Install PowerISO
  2. Under tools, select install to bootable usb
  3. Select the image file (needs to be ISO, .raw, or whatever else PowerISO can read)
  4. You need to select the non-standard "raw" option under write-options

This will write the iso/raw file to a USB drive, as bootable.

Now, on the Mac, you need to hold the Option-Key (also known as ALT on a windows-keyboard) Then you should be able to select "install XY" in the boot prompt.

However, this won't work, you'll get the

“application is damaged, can’t be used to install macOS”

error.

This is caused by expired certificate files.

So in order to fix this, do the following additional steps:

  1. Open the drive you wrote with PowerISO in TransMac.
  2. In the folder “Contents”, go to subfolder “SharedSupport”
  3. In “SharedSupport”, delete the file named “InstallInfo.plist” in the TransMac file-tree (/Contents/SharedSupport/InstallInfo.plist)

Eject the USB key, and you have a working bootable USB-stick.

0

For my own case, installed TransMac on my Windows 10 laptop but it failed to work when I am trying to burn a dmg file (macOS Big Sur) to an external USB flash drive. It says the dmg file could not be restored to a Mac volume.

Finally, I get it done by using UUByte DMG Editor. The process is quite smooth and the USB drive is recognized by my Mac Mini after burning dmg file to it. The trick in here is to format USB drive to FAT32 first before burning starts. And try to use an USB 3.0 drive as old USB 2.0 device might not be recognized by Mac.

For reference, this is a complete tutorial on how to create a macOS bootable USB from dmg file on Windows PC: https://www.uubyte.com/make-bootable-usb-from-dmg-file-on-windows.html

enter image description here

P.S. As an alternative workaround, you can also convert the dmg file to iso and burn it with ISO burning tools.

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