OS X 10.8.3 - upgrade from 0.8.2rc1
Launch attempt #1 - splash screen abruptly disappeared during "Verifying blocks..." and process became unresponsive. Killed the process and tried again.
Couldn't reproduce this, started just fine first time on OSX 10.8.4 (dev seed) upgrading from 0.8.2rc1.
No release candidate warning splashed all over this one?