When upgrading a Mac from Mac OS X 10.4 (Tiger) to 10.5 (Leopard), remember that network accounts are _not_ included if you do an archive and install and choose to migrate existing users. If a network account had its home folder at `/Users/jbloggs` then it will have been moved to `/Previous Systems.localized/2009-11-06_0346/Users/jbloggs` (although the date portion will be the date that you did your install).

This applies to [network accounts which authenticate against Active Directory and do not have a mobile account][kb].

Why my place of work used to setup Macs with the option for create mobile account at login turned off is a mystery to me.

[kb]: http://docs.info.apple.com/article.html?path=ServerAdmin/10.5/en/c7od45.html