It starts for a little while, appears a splash screen for a brief moment, and then dies.
Here's the output on console log:
07/01/12 17.59.25 [0x0-0x59059].com.yourcompany.Bitcoin-Qt[480] The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec(). 07/01/12 17.59.25 [0x0-0x59059].com.yourcompany.Bitcoin-Qt[480] Break on THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC() to debug. 07/01/12 17.59.25 [0x0-0x59059].com.yourcompany.Bitcoin-Qt[480] The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec(). 07/01/12 17.59.25 [0x0-0x59059].com.yourcompany.Bitcoin-Qt[480] Break on THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC() to debug. 07/01/12 17.59.25 [0x0-0x59059].com.yourcompany.Bitcoin-Qt[480] The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec(). 07/01/12 17.59.25 [0x0-0x59059].com.yourcompany.Bitcoin-Qt[480] Break on THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC() to debug. 07/01/12 17.59.26 com.apple.launchd.peruser.501180 Job appears to have crashed: Bus error 07/01/12 17.59.26 ReportCrash[486] Saved crash report for Bitcoin-Qt[485] version ??? (???) to /Users/looris/Library/Logs/DiagnosticReports/Bitcoin-Qt_2012-01-07-175926_Palace-of-the-Nine-Moons.crash 07/01/12 17.59.26 ReportCrash[486] Saved crash report for Bitcoin-Qt[480] version ??? (???) to /Users/looris/Library/Logs/DiagnosticReports/Bitcoin-Qt_2012-01-07-175926-1_Palace-of-the-Nine-Moons.crash
Feel free to ask for more details.