After trying to install Fedora Core 5 (which fails) I can't launch Mail.app any more. It will crash (I can send the log on request.) To make sure I've installed a clean 10.4.5 on my MBP, then installed beta2. BTW, I did the clean install after Mail started crashing. I first tried removing Parallels (using the script provided by someone - I can't find any official tool or instructions on how to remove it!) and rebooted but Mail still crashed.