Today I'm upgrading my laptop to the recently released Ubuntu 12.04 Precise Pangolin.
Even though I have my /home directory in it's own partition and the installer shouldn't wipe it out, I'm erring on the side of caution and backing up my home directory before beginning the installation.
I'm using the Linux tar command to compress and back up my home directory, but for some reason after waiting for several minutes the command kept failing with the following error message:
"file changed as we read it"
After googling for a bit I found the solution to the problem, using the --ignore-failed-read flag for tar took care of the issue.
tar --ignore-failed-read -ztvf backup.tar.gz /home/myhomedir
did the trick.