Over on Macintouch's Mac OS X Reader Reports
(well worth reading, as there's a ton of good info collected there!), Paul Christensen posted some information he received from Apple's tech support group regarding the initial setup assistant (which configures your primary user account, among other things).
According to Apple, to re-run the assistant, you need to:
- Boot into single-user mode (command-S during startup)
- Once the command-line prompt appears, type the following:
mount -uw /
mv local.nidb local.old
When you hit RETURN after typing exit, OS X will restart and the setup assistant will launch automatically. So if you've somehow messed up your primary OS X user, this is a good fix that may get you up and running again, even if re-running the OS X installer does not.