I did the 'sleep 5' thing as teodorescup suggested, but it still crashes.
This is the crash report it generated:
Add-ons:
messagingmenu%40mozilla.com:1.3.1,globalmenu%40ubuntu.com:3.6.4,edsintegration%40mozilla.com:0.5,%7Ba62ef8ec-5fdc-40c2-873c-223b8a6925cc%7D:0.18,calendar-timezones%40mozilla.org:1.2011n,%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D:1.9,langpack-en-GB%40thunderbird.mozilla.org:17.0.4,langpack-ja%40thunderbird.mozilla.org:17.0.4,%7B972ce4c6-7e08-4474-a285-3208198ce6fd%7D:17.0.4
BuildID: 20130308132820
CrashTime: 1364106687
EMCheckCompatibility: true
FramePoisonBase: 7ffffffff0dea000
FramePoisonSize: 4096
InstallTime: 1363580507
Notes: OpenGL: Tungsten Graphics, Inc -- Mesa DRI Intel(R) Ivybridge Desktop
-- 3.0 Mesa 8.0.4 -- texture_from_pixmap
ProductID: {3550f703-e582-4d05-9a08-453d09bdfdc6}
ProductName: Thunderbird
ReleaseChannel: release
SecondsSinceLastCrash: 19631
StartupTime: 1364106683
Theme: classic/1.0
Throttleable: 1
Vendor:
Version: 17.0.4
This report also contains technical information about the state of the
application when it crashed.
