I saw a post on this blog today:

http://vxlabs.com/2012/05/01/review-of-ubuntu-linux-12-04-on-the-samsung-np300v3a-core-i5-nvidia-optimus-laptop/

It suggests that there is a bug in Ubuntu’s home directory encryption that could result in data loss. I always use full disk encryption so I can’t confirm this myself. I did however follow the bug report links in the blog post and there does indeed seem to be cause for concern. If you’re already using home directory encryption in Ubuntu I suggest you check this out and by all means make sure your data is backed up. You may want to consider using Full Disk Encryption (FDE) instead of the home directory encryption option. You need the “Ubuntu Alternate CD” to install FDE.  From a security standpoint, FDE is the preferred method anyway.