Comment 69 for bug 459639

Probably none of these specifically. It's a timing issue so it depends on how fast the system is loaded from the drive. For me, faster drive or installing server software equally hid the bug. Faster drive probably because nvidia loads faster now and the server software because X was delayed a second or two.

Looking at your changes, the update that made the issue appear probably made some start-up component faster, speculatively mountall looks interesting, but I haven't checked the change log. The next update updated at least one service, potentially making the startup again slightly slower.

The triggering factors of this bug can range from hardware to installed packages to how fragmented your drive is and how much drive seeking for components happens during load. None of these are really the cause. The cause is that upstart optimized for fast start up is starting X before the underlying system is ready in some systems and under some circumstances.