Mac OS X Leopard - Before You Upgrade...

Before you install Leopard, there are a number of precautionary steps you should take.  Regardless of the upgrade or installation method, there are always potential complications.  A little planning and preparation now can prevent a disaster if something should go really wrong. 

1. BACK UP YOUR FILES AND SETTINGS!!!  We cannot stress the importance of this step enough!  The general rule is that anything you can't afford to lose should be backed up somewhere.  Burn it to a CD, copy it to a flash drive or external hard drive, just be sure to make copies of anything important.  Several of the possible installation methods will erase your hard drive.  There's really no sure-fire way of recovering data in that situation.  Other installation methods leave your files and settings in place, so you may not need that backup you made, but it's far better to have it and not need it than to need it and not have it.

In addition to backing up your files, you should make note of any settings like program configurations (e-mail account info like servers, usernames, etc), printer information (network/IP addresses, installed options, etc), servers or file shares you regularly connect to, as well as any customizations you might have made to the operating system or software that you use.  Some of these settings will carry over without issue, but you should be prepared to re-create or re-configure things should the settings not transfer gracefully.