Snow Leopard: Clean Install vs. Upgrade

	“Install me fresh!,” says the OS X DVD

I recently grabbed OS X 10.6 to install on my Apple MacBook Pro, which is a few years old now. My laptop started out with Tiger (10.4), was upgraded to Leopard (10.5) and then I just upgraded it again to Snow Leopard (10.6). The upgrade went well, but there were some things that just felt a little broken. Connections to my Time Capsule were slow, the time to put the computer to sleep was long, blue tooth devices wouldn’t power down, and certain operations just seemed slower than I expected. I thought maybe I should do a fresh/clean install, so I went to the online forums for guidance.

I found tons of people advising others that an upgrade was sufficient and that a fresh install was overkill. Well, to those people I say this: you’re wrong.

I guess I should put some context around my claim. I think the real delineation is, do you actually use your computer or is it a glorified facebook checking machine? If the latter, sure, just upgrade. But if you’re like me you’re constantly doing something to your computer. Tweaking paths, installing package managers, aliasing commands, compiling things to /usr/local, symbolically linking files to avoid other issues, etc., … all of these things leave “artifacts” or whatever you want to call them. Over time, an upgrade just can’t account for all of the stuff you’ve done.

My recommendation is to clean install doing something like this:

1. Create a Time Machine backup
2. Optional: If you have tons of media, like music, movies, etc., I recommend you just copy those somewhere manually. Restoring them manually is very fast. If time isn’t a concern, then never mind and just use Time Machine for everything.
3. Format your computer’s hard drive
4. Clean install
5. Connect to Time Machine and pull over any stuff you still want

My computer is way faster now with a fresh install. All of the oddities I had noted are gone. I also found that I only re-installed about 75% of the applications I had installed previously, which makes for a smaller footprint. Overall the only reasons I can think of why you wouldn’t want to do a fresh install would be if you make really light use of your computer, or if you simply don’t know how to go through the process of doing the install without losing valuable data. If neither of those are true then I would say it’s worth the one-time effort to get a clean system that no longer has months of junk scattered throughout the file system.

This article was edited after publication by the author on 13 Dec 2009. View changes.