I took the plunge and did something last weekend that I sort of love and sort of dread: I backed up my primary workstation, erased the hard drive, did a fresh install of Mac OS X, restored my user account, and reinstalled all my applications. I say I sort of love this because it brings out the inner geek in me: it's like getting my car detailed, every crevice cleaned out with a toothbrush, every file in /System and /Library written with pristine new copies from the installer DVD. I sort of hate it because I've done erase and installs before and I know the reality of the process: no matter how much time I spend preparing, I'm bound to forget some important installer or preference file, and I spend too much time cursing under my breath and wondering why I did the erase in the first place.

I used to do an erase and install every time a major release of Mac OS X came out. I was under the impression that the only way to get a good clean install of a new OS was to install it from scratch. I simply ignored the fact that 99% of Mac users do a standard upgrade of their OS when a new version comes out and their machines work fine for years. I thought I was technically savvy and I knew the inside information on the best way to upgrade my machines. It took several years of headaches (not to mention several years of working for Apple in a support role) for me to realize that the best way to update a machine is to simply run the default upgrade from the Mac OS X DVD. It was finally after reading a great post at John Gruber's site that I decided to update my machine to Leopard with a default update. I didn't even bother with an Archive and Install, just the regular old update. And my MacBook Pro worked great for several months.

But things changed when I made the careless mistake of using a piece of pre-release, under development software on my primary Mac OS X machine. The software in question wreaked havoc on my permissions and was likely the cause of my Aperture Library headaches a few weeks ago. A Repair Permissions helped some, but after several weeks of finding little annoying bugs caused by incorrect permissions settings on both system and user files and directories, I decided that it was time to start fresh. Yes. An erase and install was in order.

Luckily, I've learned from my experience in the past, and I did a pretty good job of preparing in advance this time. The process went as smoothly as it's ever gone. Here's what I did:

1. First I made a full cloned backup of my machine to an external hard drive using the fantastic SuperDuper from Shirt Pocket software. This is key because I can then reboot my machine from the backup and make sure that everything works properly and the backup was successful. This is also my safety net: if anything goes wrong at any point during the erase and install, I can roll back to my backup and pretend nothing ever happened. Addendum: A fully-Leopard-compatible version of SuperDuper should be released shortly. Until then, Carbon Copy Cloner is a great alternative. Or check out this thread at Shirt Pocket for more ideas. SuperDuper 2.5 is out and fully Leopard-compatible.

2. I booted my machine from the Leopard DVD and brought up Disk Utility from the DVD's Utilities menu. I used Disk Utility to repartition my hard drive, then I continued with the installer and did a standard clean install of Mac OS X.

3. When the install was complete, the machine rebooted and I created a new administrator account named "admin". I used this account to setup the machine and get it online. Then I navigated to my backup on the external drive and dragged my entire Users/charlie/ folder to the Users/ folder on my internal drive. When the folder was copied over, I went to the Accounts System Preference and added a new account named "charlie". The cool thing is that Mac OS X recognized that there was a folder with the name "charlie" already in my /Users/ folder and it asked me if I wanted to use this folder and its contents for this new account. I clicked Yes and my entire account was restored: Mail, bookmarks, iTunes music, Aperture Library, all preferences, my Keychain... everything.

4. Finally I rebooted from my "charlie" account and it was time to reinstall applications. This is usually the biggest time suck of the entire process, as it involves sitting at the machine like a monkey and inserting DVD after DVD. However in the last few years, I've started making disk images of my important installer DVDs on a large external hard drive. I do this both to protect my investment (DVDs can scratch or become unreadable), and to speed the reinstall process. Tonight after work I installed Adobe CS3, Final Cut Studio 2, Aperture, Microsoft Office, iLife and iWork 08, and the process only took me about two hours. It's nice to see those progress bars move quickly...

5. When the reinstalls were complete, I ran Software Update a few times until it told me that there were no more updates available. I did the same with the Adobe Updater app and the Microsoft Office Updater too.

As an Aperture user, one of the cool things about this is that an Aperture install only requires a few hundred megabytes. And my photos are organized as referenced images in a subfolder in my home folder, so those all got copied over in step three above. I launched Aperture after running Software Update and all my images were right where I expected them to be, with all my edits, metadata, preferences in place.

In summary, I again state for the record my firm believe that a default upgrade is the way to go for the majority of Mac users. I don't recommend otherwise unless there's a specific reason you think you need to blow your install away and start fresh. In my case, taking the time in advance to adequately prepare for an erase, combined with a complete ad bootable backup, made the erase process fairly painless and certainly less scary than it has been in the past.