How to format my mac and install fresh copy of Snow Leopard

The $29 Snow Leopard DVD can format and install without Leopard.

It is not necessary to erase and reinstall - you could just install on top of 10.5.6 if you want, and if that system is currently working well. However, if you do want to start from scratch, there is no need to install 10.5 first. You can do it all from the 10.6 disk. Put the disk in, reboot and hold down 'c'. After it boots up and you choose your language, choose Utilities -> Disk Utility. Use that to erase the hard drive. Then quit Disk Utility and proceed with the installation.

Of course, before you do that, you should have *at least one* full backup, preferably a clone of the old system, so that if something goes wrong you can go back. If you aren't sure how to do backups, see my [Mac Backup Guide|http://www.reedcorner.net/thomas/guides/backups>.

To figure out where your hard drive space is going, try getting a copy of [OmniDiskSweeper|http://www.omnigroup.com/applications/omnidisksweeper>. Don't delete stuff unless you know what it's for and that it's safe to delete, though! Also, you should make sure you're either putting your machine to sleep at night (or leaving it on) or running the maintenance scripts manually. These scripts will clean up log files, which grow over time and could be eating up your hard drive space, and other such things.

To run those scripts manually, just open the Terminal and paste the following code:

sudo periodic daily weekly monthly

Enter your password when asked, then wait until the prompt reappears (which could be a while if this hasn't been done in a while).

You can erase what you put into the trash by going to disk utility - click erase tab - click on erase free space. Maybe that will free up some more space on your hard drive. Hope this helps.

stew pit wrote:
Can i just directly re-install and format my mac using this Mac OSX 10.6 Snow >Leopard DVD?

Definitely yes.

I know that you know that there are two kind of installs for Leo: upgrade and erase and install. In principle, there would be little difference between the two. Many here say that upgrading, versus erasing and installing, is the superior procedure provided that one's prior installation is in very good condition. Others feel differently. I say just do what you prefer. My bet is that percentage-wise those getting good installs from an erase and install, particularly if all apps are reinstalled, rather than migrated, is higher than for upgrade--but probably not appreciably higher.

The processes leading to the final outcome should lead to a good outcome in either case. But, things can go wrong either way. I am not going to try to elaborate much on the specific ways that things could go wrong either way. But, for the most part, they would have to do with the way migration works and the migration technique used (if used), in the case of erase and install, and the existence of problems in the system existing prior to installation in the case of an upgrade.

To erase and install,

1. Start up from your Sno DVD, and start the installer.
2. Choose your language
3. Use the menus at the top of the next screen to start Disk Utility.
6. Erase your drive Mac extended (journaled).
7. Quit Disk Utility and continue your installation.

To do an upgrade install,

1. Start the installer from your Sno DVD either from your desktop or by starting up to the DVD.
2. Choose your language.
3. Continue your install.

Whichever kind of install you choose, you should be well backed up.

No, you delete what you put in the Trash by emptying the trash. Disk Utility has nothing to do with that. Erasing free space with Disk Utility will not give you any more space, it simply overwrites all free space on the disk to ensure no sensitive data is still lingering.

Oh, I was mistaken. Thanks for the clarification! 🙂

I'm in progress of installing a fresh copy of Snow Leopard