On the three machines on which I’ve installed Leopard so far, two went off without a hitch: a G5 iMac and a dual G5 PowerMac. The third, a MacBook Pro — ironic perhaps, in that it was the only Intel-based machine I’ve upgraded so far — not so much.

For reasons I won’t get into, I run FileVault on the MacBook Pro. I’ve gotten to used to seeing (and for the most part ignoring) messages that tell me FileVault is taking up more space than it needs and that I can fix it. I usually ignore it because 1) Space is not really at a premium on this particular laptop; and 2) It takes way too much time to do and doesn’t seem to help for very long.

So when I got this message when my MacBook was shutting down in preparation for the Leopard install, I ignored it. It think that’s what bit me. The install itself went without a hitch, but when I tried to log back into my main account, I got a message telling me my FileVault-protected Home directory couldn’t be opened. I accepted the offer to fix it, but was greeted with an “unknown error.” My main account was hosed.

Luckily, all important data had already been backed up, and the alternate account on the machine opened just fine. I wound up deleting the original account and recreating it with the same settings. So far, everything’s working fine.

Lesson learned: If you’re offered the opportunity to “fix” FileVault before installing Leopard, take it.