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macrumors newbie
Original poster
Dec 27, 2011
Is there a way of uninstalling Mountain Lion, and not losing any other installed software?

I'd be grateful if you could let me know if this is possible and if it is, a guide to how I would do this please?

Thanking you in advance.


macrumors newbie
Original poster
Dec 27, 2011
Forgot to add.

I have a MacBook Pro 13" 2.8Ghz Intel Core i7.
Purchased about a year ago.


macrumors newbie
Original poster
Dec 27, 2011
Hi MagicBoy.

You've heard of 'newbies'?
Well, I'm an extreme newbie.

I don't remember doing anything like a time machine backup.

I had notification from the App Store icon and went to the App Store.
Saw that the Mountain Lion upgrade was £13.99 and that's what I did.

There was no mention of anything else during the install.


macrumors Penryn
Feb 20, 2009
"I'd be grateful if you could let me know if this is possible and if it is, a guide to how I would do this please?"

Here's what I would do:
1. Make a BOOTABLE backup of my current internal drive (see below)
2. Reboot from the backup drive
3. Erase, and then re-partition, the internal drive
4. Install a copy of the OS you want on the internal drive
5. Create a new account on the internal drive (use your old username & password)
6. Update the OS on the internal drive "as far as it will go"
7. Use "migration assistant" to transfer your apps and user data from the backup to the internal drive.

That should do it.

You may be an "extreme newbie", but if you want to accomplish what you're asking, then you'll have to start learning! :)

I'll guess that you don't have any kind of backup right now.

Here's how to create one, cheap and easy:
1. Get one of these:
(many items shown, they all work the same, just pick one you like that's cheap)
2. Get a "bare" SATA hard drive from the vendor of your choice
3. Download CarbonCopyCloner 3.4.6 from:
4. Put the drive in the dock, connect it to the Mac, turn it on
5. The drive won't be initialized yet. Open Disk Utility (in the Utilities folder) and initialize it to Mac format, GUID partition map
6. Once initialized the drive will mount on the desktop. Give it a meaningful name.
7. Launch CCC. On the left, choose your source (internal) drive. On the right, choose your target (docked) drive
8. Choose to do a complete backup and let CCC do its thing.
9. When done, you will have a BOOTABLE backup drive.

To boot from the backup, do this:
1. Restart the Mac
2. As soon as you hear the startup sound, hold down the "option" key and KEEP HOLDING IT DOWN
3. In a few moments, the Startup Manager will appear
4. Use the mouse or the arrow keys to select the backup drive, then click to continue.
5. The Mac will boot from the backup drive.
IMPORTANT: since you "cloned" the internal to the backup, it will look EXACTLY like the internal. Check "about this Mac" under the Apple menu to be certain of which drive you are booted from. I suggest that you give the backup a different desktop picture so you can easily tell it apart from the internal.

This should get you going.


macrumors 68040
Jul 13, 2008
Uninstalling ML, as others have explained, really means erasing the drive you currently are using. Which requires a backup.

You didn't say what, if anything, you are going to replace it with. If you are going back to Lion, that can have repercussions depending on what other software you've used. In general newer applications can use older data, but older applications may not be able to use newer data. For example, some Apple Mail upgrades require upgrading Mail's database of messages; once that's done, it's very difficult to go back. You might have to download messages from a server and start all over.

If you had a backup of what you wanted to go back to it wouldn't be very difficult. If you have to ask this question, and you don't have a backup of your old system, I would recommend you don't even try it. Just resolve to make a backup BEFORE you upgrade next time.


macrumors newbie
Original poster
Dec 27, 2011
Thanks indeed for the detailed reply, Fishrrman.
As you say, I am going to have to learn, sooner or later.

Thanks also, robgendreau.
Reading what you say makes a lot of sense.

I am just going to have to put up with what's happening.
Mountain Lion is slower to start up, than Lion was.
Parallels is slow to boot up as well.

Thanks for taking the time and the advice people.


macrumors newbie
Original poster
Dec 27, 2011
Newbie is back again.

When I still had OS X Lion installed on my MacBook, I used Recovery Disk Assistant and made a back-up.

The back up is on a USB stick.
Is it possible to restore OS X Lion from that?

I have tried to do this by restarting my MacBook and holding down the Options key and I do get the boot up options but when I choose the restore option from the USB stick, it doesn't work.
I am assuming that this is because the system can see a newer version of the OS.

So, is it possible to restore from my USB stick?
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