Comment 4 for bug 358573

I've been having the same problems as well. I have my Firefox profile located under the ~/Private folder and I've had Firefox mysterious crashes multiple times per day over the last week. I finally figured out what was happening, and sure enough, after each crash I realized that ~/Private was no longer mounted.

I've seen this happen in a little as 15 minutes after running ecryptfs-mount-private. Other times the mount says up for a long time; even across suspend/resume cycles (which I thought could have been the problem, but that does not appear to be the case.)

Side note: I used encfs in earlier releases of Ubuntu (prior to when encrypted "Private" folders were offered as an out-of-the-box feature). I stored my Firefox profile on there with no unmounting issues like this (normally you had the exact opposite issue, where it was difficult to get encfs to unmount after a certain timeout period.) In any case, with Firefox running, it seems pretty likely that it would being holding files open.

I've looked around but haven't found any log messages indicates what/when/why this is happening. (ecryptfs doesn't seem to do much logging; but I haven't looked into the options)