How to create a bootable, backup Mountain Lion install disk

Need to install Mountain Lion on multiple Macs? Here's how to do it.

Read the whole story

 

[aix]

@fsck! / shomann:
I just got my MBP, this past Friday. I really don't have anything to save or backup. If I create this bootable USB flash, how do I do a clean install?

Thanks in advance

 

[Entegy]

Hold Alt on your keyboard while turning on your Mac. The USB stick should be a boot option.

 

[fsck!]

@fsck! / shomann:
I just got my MBP, this past Friday. I really don't have anything to save or backup. If I create this bootable USB flash, how do I do a clean install?

Thanks in advance

plug in the USB stick, reboot the Mac or turn it off, hold down the alt/option key during boot up, select the USB flash drive as your boot up drive and at some point you will be presented with a menu to either restore or install Mountain Lion. Just follow the process...

 

[ArmanUV]

Can anyone confirm the md5 of InstallESD.dmg?

 

[Philotech]

Trying to burn to a single layer DVD which has 4,707,319,808 bytes available and the .dmg image uses 4,348,218,934 bytes yet Disk Utility insists "The disc inserted does not have enough free space." I've tried a few different brand new DVD-R discs. I guess I'll have to burn to a dual-layer disc but that seems overkill.

Anyone else seeing this issue when trying to burn to a DVD-R?

I am running into the same issue.

Did you try mounting the dmg first to see its size decompressed? chances are the dmg is compressed and when decompressed, it is larger than 4.7GB

I have the same problem. As the size issue is rarely mentioned in all these HOW-TOs, I assume that only localized, non-English versions of the .dgm are too large to burn on a DVD (or none of the authors have actually tried their HOW-TO with a DVD).
There's a hack to reduce the size of the .dmg involving a terminal command I don't recall exactly I thing it was HDIUTIL with a long trail of parameters. That did the trick for me.

 

[Philotech]

It would save quite a bit of time during installation to use the method outlined here:
http://forums.macrumors.com/showthread.php?t=1401529

The straigt-forward copied InstallESD will first copy all packages to your internal HD, before starting installation. Doing so adds about 10-20 minutes to your installations.

I have read that thread and I'm still not sure what's the main advantage. Is it really that the simple .dmg burnt in accordance with the ars technica how-to still downloads most of the content of itself, that parts that actually make up ML, from the internet again?
Other than that, I understand that the macrumors version does not create a recovery partition, so there are reasons not to go that way.

 

[aix]

@fsck! - Thanks for the reply. Will this clean install, also create a recovery partition?

Totally new to MAC OS, so Ia ma trying to catch up.

Thanks again,
James

 

[Danteal56]

Followed the instructions and no luck.

The drive shows up when I option boot but after selecting that drive around 5 seconds later the apple logo turns into a "do not enter" (circle with a line through it) logo.

Also mounting the DMG before writing it to the flash drive did NOT get rid of the error at the end of restoring to the flash drive. At least not for me.

I'm having the exact same problem as you. Any luck yet?

 

[Mad Hacker]

Trying to burn to a single layer DVD which has 4,707,319,808 bytes available and the .dmg image uses 4,348,218,934 bytes yet Disk Utility insists "The disc inserted does not have enough free space." I've tried a few different brand new DVD-R discs. I guess I'll have to burn to a dual-layer disc but that seems overkill.

Anyone else seeing this issue when trying to burn to a DVD-R?

I am running into the same issue.

Did you try mounting the dmg first to see its size decompressed? chances are the dmg is compressed and when decompressed, it is larger than 4.7GB

Yep. Mounted it appeared to be the same size so I don't think it's compressed (or the compression didn't gain much.)

 

[richard2]

Trying to burn to a single layer DVD which has 4,707,319,808 bytes available and the .dmg image uses 4,348,218,934 bytes yet Disk Utility insists "The disc inserted does not have enough free space." I've tried a few different brand new DVD-R discs. I guess I'll have to burn to a dual-layer disc but that seems overkill.

Anyone else seeing this issue when trying to burn to a DVD-R?

I am running into the same issue.

Did you try mounting the dmg first to see its size decompressed? chances are the dmg is compressed and when decompressed, it is larger than 4.7GB

Yep. Mounted it appeared to be the same size so I don't think it's compressed (or the compression didn't gain much.)

$ hdiutil imageinfo "/Applications/Install OS X Mountain Lion.app/Contents/SharedSupport/InstallESD.dmg"
Format Description: UDIF read-only compressed (zlib)
Class Name: CUDIFDiskImage
Checksum Type: CRC32
Size Information:
	Compressed Ratio: 0.98869885061768925
	Total Empty Bytes: 372972544
	Sector Count: 9286972
	Total Bytes: 4754929664
	CUDIFEncoding-bytes-wasted: 0
	Total Non-Empty Bytes: 4381957120
	CUDIFEncoding-bytes-in-use: 4332436200
	Compressed Bytes: 4332436200
	CUDIFEncoding-bytes-total: 4332436200

According to hdiutil, the image is compressed, and its decompressed size is 4.43 GiB, which exceeds the maximum capacity of a single-layer DVD (4.38 GiB). The image must therefore be written to a dual-layer DVD or a USB Flash drive.

 

[Philotech]

As posted above, there is a way to optimize the dmg so it will fit on a single-layer DVD by using HDIUTIL.
The command to use is: hdiutil makehybrid -hfs -o <path-to-destination-dmg> <path-to-source-dmg>

For a more detailed description, use Google or ook here for example: http://forums.macrumors.com/archive/ind ... 87589.html

 

[fsck!]

Trying to burn to a single layer DVD which has 4,707,319,808 bytes available and the .dmg image uses 4,348,218,934 bytes yet Disk Utility insists "The disc inserted does not have enough free space." I've tried a few different brand new DVD-R discs. I guess I'll have to burn to a dual-layer disc but that seems overkill.

Anyone else seeing this issue when trying to burn to a DVD-R?

I am running into the same issue.

Did you try mounting the dmg first to see its size decompressed? chances are the dmg is compressed and when decompressed, it is larger than 4.7GB

Yep. Mounted it appeared to be the same size so I don't think it's compressed (or the compression didn't gain much.)

$ hdiutil imageinfo "/Applications/Install OS X Mountain Lion.app/Contents/SharedSupport/InstallESD.dmg"
Format Description: UDIF read-only compressed (zlib)
Class Name: CUDIFDiskImage
Checksum Type: CRC32
Size Information:
	Compressed Ratio: 0.98869885061768925
	Total Empty Bytes: 372972544
	Sector Count: 9286972
	Total Bytes: 4754929664
	CUDIFEncoding-bytes-wasted: 0
	Total Non-Empty Bytes: 4381957120
	CUDIFEncoding-bytes-in-use: 4332436200
	Compressed Bytes: 4332436200
	CUDIFEncoding-bytes-total: 4332436200

According to hdiutil, the image is compressed, and its decompressed size is 4.43 GiB, which exceeds the maximum capacity of a single-layer DVD (4.38 GiB). The image must therefore be written to a dual-layer DVD or a USB Flash drive.

This is true. Lion was the same way by the way. I'm ok with wasting a DL DVD on it. I still have a stack I bought two years ago, I probably get to use 1 or 2 a year... :bigdumbgrin:

 

[fsck!]

@fsck! - Thanks for the reply. Will this clean install, also create a recovery partition?

Totally new to MAC OS, so Ia ma trying to catch up.

Thanks again,
James

Yes, at least it will attempt. If your system has Lion and a recovery partition already in it, the ML installation will attempt to update the existing recovery parition to ML. So long as it is a GUID partition and the size is right, it should have no problems doing that. Your other option is to completely delete the partitions from the drive before installing ML via diskutil (you should have access to diskutil when you boot off of the ML disk) such that the installer does everything from scratch.

 

[fedward]

As noted in the comments, however, mounting the InstallESD.dmg file before performing the restore process avoids triggering the error message.

Not quite. Mounting it and then using the mounted disk partition as the source is what fixes it.

 

[aix]

@fsck! - Thanks for the reply. Will this clean install, also create a recovery partition?

Totally new to MAC OS, so Ia ma trying to catch up.

Thanks again,
James

Yes, at least it will attempt. If your system has Lion and a recovery partition already in it, the ML installation will attempt to update the existing recovery parition to ML. So long as it is a GUID partition and the size is right, it should have no problems doing that. Your other option is to completely delete the partitions from the drive before installing ML via diskutil (you should have access to diskutil when you boot off of the ML disk) such that the installer does everything from scratch.

Thanks again. I'm installing now. In diskutil, there is a "disk2" that has an icon with a earth looking globe on top of a HDD. I assume that is the Internet Recovery partition? Finished. I decided to wipe the partition and create a new one. Hopefully it created the recovery partition also. I'm downloading some apps, so I'll have to reboot and command-r to see if there is a recovery partition.

 

[Jubijub]

I do these installs because I don't trust that all the fluff from my previous install is removed by the installer. When I upgrade to 10.8 from 10.7, I will backup, perform this USB restore disk function, COMPLETELY erase my MBA, and start from scratch.

Clean is good.

+1 here

I do a bit of dev, and I find it much cleaner to start from scratch rather to debug python libraries, path, etc...
I always find my system much snappier in the end, and I also ensure it resets my prefs to sensible defaults for the new version.

I have to admit that compared to my old days on windows, osX doesn't self-bloat as older windows would

 

[deckeda]

So... anybody found a way to install on older hardware? I got a Mac Pro 1,1 and I can't believe it can't handle Mountain Lion...

There is zero way really.

The problem is your video chipset. The maker of said chipset never released x64 drivers for it. ML *requires* x64 kernel extensions. Unlike SL and Lion which could take x32 and x64 extensions.

Ah. What if I have updated the video card from stock? I replaced the stock GeForce 7300 with a Radeon 5770. Any way to make it work? Thanks...

It's been done, but it's easier to shoehorn OS X onto a PC. http://www.jabbawok.net/?p=47

 

[deckeda]

I do these installs because I don't trust that all the fluff from my previous install is removed by the installer. When I upgrade to 10.8 from 10.7, I will backup, perform this USB restore disk function, COMPLETELY erase my MBA, and start from scratch.

Clean is good.

+1 here

I do a bit of dev, and I find it much cleaner to start from scratch rather to debug python libraries, path, etc...
I always find my system much snappier in the end, and I also ensure it resets my prefs to sensible defaults for the new version.

I have to admit that compared to my old days on windows, osX doesn't self-bloat as older windows would

Right --- OS X doesn't self bloat, and newer versions installed atop older ones aren't at a disadvantage.

The build-up of cruft comes from migrating your user account. Years of outdated stuff live in ~/Library because applications don't need uninstallers and so most don't include them. Even for apps that get updated over the years, the new versions don't always purge older pieces/parts of the previous. Adobe has been guilty of this, for one.

 

[Jason T. Miller]

I have read that thread and I'm still not sure what's the main advantage. Is it really that the simple .dmg burnt in accordance with the ars technica how-to still downloads most of the content of itself, that parts that actually make up ML, from the internet again?
Other than that, I understand that the macrumors version does not create a recovery partition, so there are reasons not to go that way.

Even in cases where you don't care about the recovery partition, or are willing and able to hack into place later, I wouldn't recommend the "shortcut" method, for the simple reason that it's not supported, and, therefore, Apple is free to break it at any time by doing additional mandatory stuff during "stage 1" of the install process (assuming, of course, that it's not already broken in subtle ways already). By comparison, the InstallESD.dmg mechanism is used by both the Mac App Store and NetInstall (c.f. the contents of a Lion/ML NetInstall.dmg with the MAS InstallESD.dmg), so Apple can't inadvertently bork it without also breaking the ordinary installation processes. And the InstallESD process, in spite of the fact that it's never appeared in "official" documentation, has even been recommended to enterprise customers by Apple.

Per Internet transfers: I've installed Lion, most of the ML DP releases, and ML GM from both USB sticks and hard drive partitions, all imaged from InstallESD, with no Internet connection at all. If you watch the logs during the "stage 1" installer process, there is a point where it looks for updates, and OS X "combo" updaters are typically 1GB+, so I can understand the confusion. If you must (?) have an Internet connection active during the install, you can minimize update size by using the ESD image from the latest "point release" application bundle to install. Finally, I suspect a more supportable hack to avoid Internet updates would be to apply the equivalent of

defaults write /Library/Preferences/com.apple.SoftwareUpdate CatalogURL http://localhost:8088/index.sucatalog

to the install image, possibly replacing "localhost" with the hostname of an actual local Software Update server if you happen to have one.

Rather than use a USB stick, my usual practice is to create a small partition on my FireWire backup RAID, restore the installer image to this partition, then use the (poorly-documented) "gpt" command-line tool to set its GPT partition type to Apple_Boot (GUID 426F6F74-0000-11AA-AA11-00306543ECAC) so it's bootable and mountable as an HFS+ volume in OS X, but not mounted (or even visible in Disk Utility) by default.

 

[Philotech]

I have read that thread and I'm still not sure what's the main advantage. Is it really that the simple .dmg burnt in accordance with the ars technica how-to still downloads most of the content of itself, that parts that actually make up ML, from the internet again?
Other than that, I understand that the macrumors version does not create a recovery partition, so there are reasons not to go that way.

Even in cases where you don't care about the recovery partition, or are willing and able to hack into place later, I wouldn't recommend the "shortcut" method, for the simple reason that it's not supported, and, therefore, Apple is free to break it at any time by doing additional mandatory stuff during "stage 1" of the install process (assuming, of course, that it's not already broken in subtle ways already). By comparison, the InstallESD.dmg mechanism is used by both the Mac App Store and NetInstall (c.f. the contents of a Lion/ML NetInstall.dmg with the MAS InstallESD.dmg), so Apple can't inadvertently bork it without also breaking the ordinary installation processes. And the InstallESD process, in spite of the fact that it's never appeared in "official" documentation, has even been recommended to enterprise customers by Apple.

Per Internet transfers: I've installed Lion, most of the ML DP releases, and ML GM from both USB sticks and hard drive partitions, all imaged from InstallESD, with no Internet connection at all. If you watch the logs during the "stage 1" installer process, there is a point where it looks for updates, and OS X "combo" updaters are typically 1GB+, so I can understand the confusion. If you must (?) have an Internet connection active during the install, you can minimize update size by using the ESD image from the latest "point release" application bundle to install. Finally, I suspect a more supportable hack to avoid Internet updates would be to apply the equivalent of

defaults write /Library/Preferences/com.apple.SoftwareUpdate CatalogURL http://localhost:8088/index.sucatalog

to the install image, possibly replacing "localhost" with the hostname of an actual local Software Update server if you happen to have one.

Rather than use a USB stick, my usual practice is to create a small partition on my FireWire backup RAID, restore the installer image to this partition, then use the (poorly-documented) "gpt" command-line tool to set its GPT partition type to Apple_Boot (GUID 426F6F74-0000-11AA-AA11-00306543ECAC) so it's bootable and mountable as an HFS+ volume in OS X, but not mounted (or even visible in Disk Utility) by default.

Thanks for the exhaustive explanation. in the meantime, I went the standard route of creating an install disk with the NetInstall.dmg and turned off WiFi during install. Everything went smoothly (or as smoothly as it gets using a DVD for lack of an USB stick with 8 GB or more). I did have to optimize the .dmg first using HDIUTIL to make it fit on an SL DVD with just 4.7 GB.

 

[Tomovich]

Hello

After I downloaded Mountain Lion, the installer started automatically and I went through with it. When my MBP restarted and I saw the progress bar, I canceled the update since I wanted a "fresh" install.

After canceling it and restarting Lion, I made an install disk as described in the article. But when I try to install from the install disk, once it's loaded, I get an error message.

I think the Mountain Lion installer deleted the "necessary file needed to make your own install disk". How can I get this file back?

The install disk I made showed no errors when making it, only when loading/starting up the Mountain Lion installer.

 

[gustav_1]

I feel the same way. I keep my Mac in top notch working condition. I run maintenance scripts on a regular basis, run Onyx and AppCleaner regularly as well. Even at that, I think a clean install is your best bet. If you find something doesn't work quite right after upgrading, you'd be beating your head against the wall not knowing if it is a bug or the result of a leftover from the previous OS and chances are you will wind up wiping and installing again.

To present the opposite point of view, I never do clean installs when upgrading. I also don't run Onyx or anything like that. The OS X cleans up logs on its own, and a few orphaned plist files do not slow down the machine at all, and my disk isn't close to being full.

If I ever find something doesn't work quite right, I'll just clean install then, and move my stuff in from a backup. Never had to do that yet, though. To me, the time saved from reinstalling everything is worth the risk. So far, it has paid off.

 

[fteoOpty64]

Why doesn't Apple just integrate this ability into the upgrade/installation experience?

It's been asked. They don't care, everything is over the Internet now and screw you if you can't download it (but please come to an Apple Store even if the closest one is an hour's drive).

I really wish the upgrader offered the ability for the user to plug in a USB stick and make a backup installer, but Apple doesn't seem to realize not everyone has broadband or a bandwidth limit that makes downloading 4.34GB in a pinch viable.

You are right!. Still if Apple just issued some "pre-install notes" it would help a ton to lots of people. Like do a backup of the .app file before clicking "Continue". It actually means they are expecting users to download several times/copies, so they can "inflate" the number of downloads ?!. Maybe, maybe not, they might not care what-so-ever ...

 

[AMCarter3]

Can anyone tell me if it is possible to put the Mtn Lion install DMG file in one partition on a Flash Drive and put DiskWarrior's install file in another partition on the same Flash drive?

 

[johninparis]

Important warning: the OS X installer will delete the necessary file needed to make your own install disk once it runs. Therefore, you need to either make a copy of the installer outside of the Applications folder or make your install disk before upgrading.

I see this warning a lot, but I have yet to run into it when doing a fresh install to and from an external disk. I have so many 2.5" drives left over from upgrades over the years that I use them instead of Flash drives, with the benefit that they hold a lot more and tend to be faster than the cheap Flash memory used in USB sticks.

I do a full, regular install to the external drive from the installer (Mountain Lion, and Lion before it). When the process is done, the ML installer is still in my internal drive's Applications folder. So I can simply copy it over to the external drive. Now, I have a backup drive (with the full OS, as well as a recovery partition), as well as the normal installer. Booting off of the external drive allows me to do a clean install or upgrade on my internal drive.

And, at least with clean installs, the installer on the external drive still isn't deleted. I usually upgrade my internal hard drive to max capacity available when I upgrade my OS, so my install are almost always clean installs - and I free up yet another 2.5" drive to turn into an external drive. But as a result, I don't know if the installer deleting itself is the end of a successful upgrade, or just behavior of an older version of the (Lion) installer that no longer happens.

TL;DR: Make a clean install to an external drive, copy the installer (which won't have self-destructed) to the external drive, and use the external drive as your installation source. You avoid weird work-arounds, and you don't need to re-download the installer.

 

[stokestack]

Some folks might have a slight problem when trying to restore from the dmg–it sometimes fails towards the end. I found that just mounting the InstallESD.dmg and using that as the source will be fine.

Unfortunately the resulting boot drive can't be "blessed" as a boot disk when you try to select it as the startup disk in System Preferences. If you boot with the Option key, it will show up as bootable but the boot will fail, showing an circle-with-line-through-it icon.

 

[HazMatt]

Can anyone tell me if it is possible to put the Mtn Lion install DMG file in one partition on a Flash Drive and put DiskWarrior's install file in another partition on the same Flash drive?

I'm several months late, but I can confirm that you can indeed do what you're asking. I split out 8 GB from my 16 GB flash drive to set up a 10.8 boot / install partition, with the other half dedicated to personal files.

 

[thinkdunson]

what if you've already burned the installer to a DVD… is there a way to pull the disk image back off in order to create another bootable disk?

 

[John Redoe]

Is there some way I can purchase and download this without going through the app store? I want to download it on my Windows PC at work and take it home on a flash drive.

App Store is the only way.

No, it's not (but you need an Apple's machine to do it).

1. Try to reinstall OS X on your USB Stick from the Recovery HD (yes, you can't; but this will download your own late 2012's compatible InstallESD.dmg).
2. Boot Mountain Lion like always you do, look into your USB drive and follow the upper tutorial.

You are welcome.

 

[estherau]

When i was making the bootable flashdrive, after I had finished I forgot to move the installer back to the applications folder before running it. My mountain lion is slow and a bit flakey. Could this be the cause? Can I run the installer again?