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Dear Aunt TUAW: How do I install a Lion partition on my MacBook Air?

by Erica Sadun Feb 25th 2011 at 2:00PM

Dear Aunt TUAW,

I'm in the Mac Developer program and I'd really like to be able to install Lion on my MacBook Air as a second OS. What are the best strategies to do this? Is it worth going out and buying a second SSD drive and swapping that out with my primary Snow Leopard system?

Thanks for letting me know!

Love and Kisses,

Your nephew G

Dear G,

Auntie turned to one of our former blogging staff to see if your swap-the-SSD approach was doable. Apple repair expert Josh Carr advised against. "You're talking about the new MBA with the blade SSD," he said. "Swapping the drives out isn't hard, just dangerous -- static could kill the SSD. It would require a screw driver and a second unit for the second OS. There are a lot of places selling the blade drives now, but it seems like it wouldn't be worth the effort. The older style SSDs would be even more difficult."

Instead, Josh advises that you just partition your drive. Although the drive size is small, you only need 10-20GB to get a good test environment set up for Lion. Plus, there are a number of simple ways you can set up your preferences to share your home and applications between both partitions.

First, you'll want to partition your drive. Disk Utility allows in-place partitioning if your drive is not particularly fragmented. Before doing anything, back up your drive and verify your backup.

Then launch Disk Utility, click your main drive, click partion, click +, adjust the size of your partitions, and click Apply. Disk Utility should confirm that it will be able to do the in-place partion without erasing. If it does not, do not click Apply. You may need to use a third party tool instead.

You'll probably also want to run Software Update before doing any installations, to bring your system up to date and avoid any dangling prerequisite updates that might snag you during the install process. Repairing your disk is also a good preparation step.

You're now ready to install the new OS. When doing so, be sure to select the correct partition -- a little oversight that came to bite one of our TUAW family yesterday.

If you're doing any kind of OS X install from a thumb drive, don't forget: make sure your drive is partitioned using GUID and formatted with HFS+. As with any OS X install, you can use Disk Utility to restore an install image to that USB drive and then use Startup Disk to select that drive.

Once you've installed Lion, you can take advantage of several standard OS setup features to allow you to better share your computer between two operating systems. Here are two suggestions courtesy of Uncle TJ Luoma.

First, you can take advantage of the advanced options in System Preferences > Accounts to redirect an account's home folder. Right-click the account name to access those Advanced Settings and then edit the "Home directory:" field (there's an interactive Choose... to simplify selection) so both partitions share the same home folder on the larger disk segment of your system. Once set, you will need to restart your computer.

Second, you can share applications by linking your Snow Leopard /Applications folder to the home folder ~/Applications directory used by Lion.

Obviously, when performing these tricks, try to avoid renaming or otherwise fussing with your partitions after setting up your links.

Best of luck with your new OS install!

Hugs and kisses,

Auntie T.



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Dear Aunt TUAW, I'm in the Mac Developer program and I'd really like to be able to install Lion on my MacBook Air as a second OS. What...
 

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21 Comments

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Bavich

Hi,
Could you please explain how link Snow Leopard Applications with Lion Application.
Tks!

March 01 2011 at 6:22 AM Report abuse rate up rate down Reply
Tom Gregson

"you can share applications by linking your Snow Leopard /Applications folder to the home folder ~/Applications directory used by Lion"

Could Auntie expand on sharing applications please and how you would avoid them crashing when unable to access the relevant preferences.

February 26 2011 at 9:02 AM Report abuse rate up rate down Reply
1 reply to Tom Gregson's comment
Pooria

Yes, please talk more about this kind of issues...

February 27 2011 at 8:04 PM Report abuse rate up rate down Reply
matthewmiller12345

What about a regular MacBook? I have a MacBook with a (not from Apple) 320GB hard drive and 2 GB of ram running Snow Leopard 10.6.6. It's Core 2 Duo with a Nvidia 9400M graphics chip.

February 26 2011 at 3:21 AM Report abuse rate up rate down Reply
cycomachead

I tried linking my home folder, but when I restarted Lion right after it didn't work correctly with System Preferences crashing on open and my settings all disappeared.

Lion seems neat, and partition the disk is relatively easy to do, so as long as you've got a backup it's not too risky. You could also use a small (or large) external drive to install Lion which would work well too, but it would be a little slower.

February 26 2011 at 12:39 AM Report abuse rate up rate down Reply
2 replies to cycomachead's comment
ianlive

Had the very same issue with System Prefs. Had to reinstall on the partition. You as well?

Did you try linking your Apps folder from you main partition?

February 26 2011 at 10:02 PM Report abuse rate up rate down Reply
cycomachead

I had to reinstall. Not the first time though. (i've done it again though because I screwed up my Lion partition in other ways too, but I don't have data there.)

I never tried my apps folder. It's easy enough to access my main apps folder.

February 27 2011 at 12:54 AM Report abuse rate up rate down Reply
2020Tech

Why not just use an external hard rive with Lion on it and boot it from that? It would be cheaper and alot less dangerous.

February 25 2011 at 5:10 PM Report abuse rate up rate down Reply
1 reply to 2020Tech's comment
cycomachead

It's not necessarily cheaper. I mean, if you don't have a spare drive, then it's more money. It's also more cumbersome to have a second drive when you weren't planning on it and can use more battery (For laptop users).

Repartitioning the drive can be very easily done now and is safe as long as you don't try to write loads to the disk while it's going on.

February 26 2011 at 12:49 AM Report abuse rate up rate down Reply
howie

Just buy an external USB hard drive! If you're REALLY a developer, you would have had the forethought, and intelligence to understand that.

February 25 2011 at 3:40 PM Report abuse rate up rate down Reply
elijahpr

He said he's IN the Mac Developer Program... that definitely implies he's a dev.

I'd like to get my hands on Lion to try this. Any comment on how stable/unstable it is? G, if you read this, let us know how the install goes!

February 25 2011 at 3:39 PM Report abuse rate up rate down Reply
1 reply to elijahpr's comment
dave.healey

Stability probably will vary depending on the user and their usage. So far, I've been using it for several hours, I haven't tried every app in my arsenal, I'm constantly using the obvious onse like iChat, Mail, iPhoto & Safari without issue (apart from the minor grievances mentioned in my earlier post.

February 25 2011 at 4:06 PM Report abuse rate up rate down Reply
leslienetwcape

Would installing Lion on a USB flash drive work?

February 25 2011 at 3:39 PM Report abuse rate up rate down Reply
1 reply to leslienetwcape's comment
dave.healey

In my experience trying to run an OS on a USB Flash Drive is painfully slow.
I use one as an emergency disk with a thin OSX installed to do things like check the internal HDD etc, but its cringe worthily slow!

If you don't have a spare bit of room on your Internal drive to re-partition and test, use an external firewire or usb drive, at least it will be usable but again they not going to perform as well as the internal SATA bus.

February 25 2011 at 4:01 PM Report abuse rate up rate down Reply
dave.healey

Probably a bit long winded, but I did the following:

1. I shrunk my main "MacHD" partition running 10.6.5 down from 800Gb to 400Gb (that still left 200Gb of empty space as I was only using just under 200Gb).

2. Then I partitioned up the empty space as a second "MacHD 2" empty partition.

3. I used Carbon Copy to duplicate the first partition to the second partition, so I have my original 10.6.5 intact but all my working configuration now duplicated on partition 2.

4. I upgraded 10.6.5 on the 2nd partition to 10.6.6 as its a pre-requisite to installing 10.7 (Lion).

5. Downloaded Lion through the Mac App Store using my redemption code and upgraded the 2nd partition to Lion.

Its working really well actually, so far I have been using Lion for general usage, allowing me to evaluate it better than just booting up temporarily to check it out. Of-course, I can always switch back to my first partition if things change.

Early developer copy bugs are apparent, like LaunchPad seems to crash every time you first create an application group and try to rename it. The second time allows you to rename but always removes the last character, so I have got used to putting a space at the end of my naming conventions :-)

Also, I decided to tidy up the 10.7 by removing unwanted apps and apps that are no longer compatible. LaunchPad seems to be stuck with all the original apps from the original upgrade, so I have had to create a "Deleted Apps" folder to keep things tidier.

Other things I haven't seen mentioned anywhere else is there is a nice suite of voices in 10.7. Some sound particularly life-like. There's a new UK Male voice called "Daniel" which is impressive for computer generated!

The Mail.app 5 is cool, I'm using that extensively, but another little bug I've noticed is sometimes the main window disappears as if you've hidden it. The only way to get it back is to close and re-open the app. This could be an issue related to Spaces though, because I use that extensively too and I think I've witnessed this problem in the past.

Oh and Terminal has a nice new theme called "Silver Aerogel" :-)

February 25 2011 at 3:36 PM Report abuse rate up rate down Reply
1 reply to dave.healey's comment
ianlive

Thanks for mentioning those bugs Dave. I ran into the LaunchPad one as well. I also followed the advice in the article and linked my home folder on my 50GB Lion partition to my home folder on my Snow Leopard partition of my MBPro.

Colossal consequences. Permission errors, not able to access files in the Finder and System Preferences would crash everytime it launched, preventing me from reverting my home folder back to it's original.

Had to reinstall Lion. Anyone else try linking home folders as described above?

February 26 2011 at 9:59 PM Report abuse rate up rate down Reply
Ahmed Hassan

I don't think G's a developer at all! I think G procured Lion by other means (*wink *wink) because surely every developer knows how to do it?...

February 25 2011 at 2:41 PM Report abuse rate up rate down Reply
3 replies to Ahmed Hassan's comment
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