I have downloaded this installer from a torrent site and not from the MacAppStore because it was slow to download followed the advice here but couldn't do because the installer is in DMG format not in .App format.

Could any please tell me how to do it?

  • Could you open your .dmg file and provide its content within your question? So that someone might see where your problem is.
    – dan
    Jun 25, 2015 at 10:26
  • 5
    Downloading any sort of installer or application from a torrent site is a great way to make your computer part of a botnet. I wouldn't advise it. Jun 25, 2015 at 11:10
  • 2
    I strongly advise you against downloading any software from torrent sites. It puts your computer at risk and as William T. Froggard says in his comment it may have serious consequences for your and other's security (see en.wikipedia.org/wiki/Botnet). So delete the DMG file and download the Yosemite installer from the Mac App Store, it may need longer to download, but you can definitely trust it. Then follow the instructions in the link you provided or in emilycurious's answer below.
    – jaume
    Jun 25, 2015 at 19:49

2 Answers 2


See How to make a bootable OS X 10.10 Yosemite install drive at macworld.com.

Option 2 worked for me:

  1. Find the Yosemite installer on your Mac. It’s called Install OS X Yosemite.app and it should have been downloaded to your main Applications folder (/Applications).

  2. Right-click (or Control+click) the installer, and choose Show Package Contents from the resulting contextual menu.

  3. In the folder that appears, open Contents, then open Shared Support; you’ll see a disk image file called InstallESD.dmg.

  4. Double-click InstallESD.dmg in the Finder to mount its volume. That volume will appear in the Finder as OS X Install ESD; open it to view its contents.

  5. Several of the files you’ll need to work with are hidden in the Finder, and you need to make them visible. Open the Terminal app (in /Application/Utilities), then type (or copy and paste) the following command, and then press Return:

    defaults write com.apple.finder AppleShowAllFiles 1 && killall Finder

    (This tells the Finder to show hidden files—we’ll re-hide such files later.)

  6. Launch Disk Utility (in /Applications/Utilities) and then drag BaseSystem.dmg (in the OS X Install ESD volume) into Disk Utility’s left-hand sidebar.

  7. Select BaseSystem.dmg in Disk Utility’s sidebar, and then click the Restore button in the main part of the window.

  8. Drag the BaseSystem.dmg icon into the Source field on the right (if it isn’t already there).

  9. Connect to your Mac the properly formatted hard drive or flash drive you want to use for your bootable Yosemite installer.

  10. In Disk Utility, find this destination drive in the left sidebar. You may see a couple partitions under the drive: one named EFI and another with the name you see for the drive in the Finder. Drag the latter—the one with the drive name—into the Destination field on the right. (If the destination drive has additional partitions, just drag the partition you want to use as your bootable installer volume.)

  11. Warning: This step will erase the destination drive or partition, so make sure that it doesn’t contain any valuable data. Click Restore, and then click Erase in the dialog box that appears; if prompted, enter an admin-level username and password.

  12. Wait for the restore procedure to finish, which should take just a few minutes.

  13. Open the destination drive—the one you’re using for your bootable installer drive, which has been renamed OS X Base System. Inside that drive, open the System folder, and then open the Installation folder. You’ll see an alias called Packages. Delete that alias.

  14. Open the mounted OS X Install ESD volume, and you’ll see a folder called Packages. Drag that folder into the Installation folder on your destination drive. (You're replacing the deleted Packages alias with this Packages folder.) The folder is about 4.6GB in size, so the copy will take a bit of time, especially if you’re copying to a slow thumb drive.

  15. Also in the mounted OS X Install ESD volume, you’ll find files named BaseSystem.chunklist and BaseSystem.dmg. Copy these files to the root (top) level of your install drive (OS X Base System, not into the System or Installation folder).

  16. Eject the OS X Install ESD volume. You’ll likely want to re-hide invisible files in the Finder. Open the Terminal app, type (or copy and paste) the following command, and then press Return:

    defaults write com.apple.finder AppleShowAllFiles 0 && killall Finder

You now have a bootable Yosemite install drive. If you like, you can rename the drive from OS X Base System to something more descriptive, such as Yosemite Installer.

  • 2
    While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes.
    – jherran
    Jun 25, 2015 at 12:53
  • 1
    pasting it in, I get "too long by 2827 characters" - I'm pretty sure he's gonna be reading it within a reasonably safe time span, and if not, there is always this cool app called google... Jun 25, 2015 at 13:01
  • 4
    @emilycurious whats wrong with writing your own answer :)
    – Downgoat
    Jun 25, 2015 at 13:28
  • 1
    @emilycurious I've edited your answer and added and formatted option 2 (the one you say worked for you - you don't have to add the whole document, only the part that is relevant). Your answer has now a value by itself, should the linked article at macworld.com go offline.
    – jaume
    Jun 25, 2015 at 19:23

Show hidden files in a folder...just TOGGLE IT ON...

Use Command+Shift and press "." (Period)

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .