Leopard represents a major leap in OS X. As such, there are some major changes under the hood that you should respect when considering moving to Leopard. If you rely on your Mac for day to day business needs, you are best off waiting for a couple of weeks and following news reports, while the rest of us geeks figure just what does and what does not work. You might also be wise to wait for 10.5.1. Apple has a history of releasing a .1 release within a month or so, quick fixing any major issues that are found by the general public.
When you do decide to move to Leopard, here are some tips to consider:
Make a complete archival backup of your system
Use a cloning backup program such as Super Duper to archive your computer to an external drive. I use the term archive because I suggest putting this drive away and not touching it for several months while you decide how well Leopard is working for you. Should you ever need to move back to Tiger, you can clone back this older backup, after saving off any data you added or changed while using Leopard.
Erase and Install
If you have several good backups of your system you might be best off erasing your system and installing Leopard clean, vs. upgrading or archive and installing. You can then use the migration assistant to copy your users and data from the archive backup you made in the first step above. (There is a method to my madness)
Time Machine vs. Super Duper
Time Machine promises to be a wonderful archival backup system, however it is new and has no track record for reliability. If you plan on using Time Machine, I suggest using a separate, large hard disk (because time machine will keep old data as long as it can!) for time machine, and a separate drive for your clone backup using Super Duper.
Three disks?!
Yes. Your data is very important. So now you have one drive with your tiger archive, one for a super duper clone backup and one for your Time Machine. Should Leopard prove great for you, you can eventually repurpose your original Tiger archive drive for Time Machine or a second Super Duper backup. Keep one offsite. You’ll thank yourself later. Drives are cheap these days.
Install Applications
After installing Leopard, install any apps that need reinstalling and keep a log, so if your machine does start acting oddly, you can contact the appropriate developer.
Beware plugins!
Quicktime Codecs, such as XIPH, iTunes Plugins, haxies, Little Snitch 1.x and other applications that hook in or extend the operating system can and probably will cause some issues on Leopard. The underpinnings have changed and thus the rules for these extensions have also. If you are having odd behavior, check the following locations for installed software. If you have an uninstaller, use that to remove the software, over uninstalling by hand:
Home Folder Locations
/Users/YOUR_HOME/Library/InputManagers/
/Users/YOUR_HOME/Library/iTunes/iTunes Plug-ins/
/Users/YOUR_HOME/Library/QuickTime/
Top Level System Locations
/Library/InputManagers/
/Library/iTunes/iTunes Plug-ins/
/Library/QuickTime/
Beware StartupItems
Some applications install startup unix scripts. You won’t want to remove these by hand, but rather use the application’s uninstaller. To see what you might have installed that runs when you boot your machine, look in the folder:
/Library/StartupItems/
You might see Retrospect, or some Final Cut Pro, mySQL, Parallels, etc startup items in here. If so, contact the developer to make sure you have Leopard compatible versions.
Clear the caches
If you are experiencing any oddities, it is known that cache data from your Tiger system may cause problems. Caches are files to help speed up operations and I don’t know why the installer does not nuke them for you. You can find these cache folders to delete at:
/Library/Caches/
/Users/YOUR_HOME/Library/Caches/
Enjoy!
With these simple precautions you are well on your way to enjoying Leopard and its many new, wonderful features!