Comment 1 for bug 1328107

This report came up in a google search just as I was giving up; just to make it clear for the next person who find this bug:

"If a user was created on an earlier [than 14.04] release [of Ubuntu]" then you'll have trouble. The fix referred to under that "user namespaces" subsection is:
   sudo usermod -v 100000-200000 -w 100000-200000 YOURUSER
where YOURUSER is a user that's been around since pre-14.04 days.

This bug report is particularly helpful if, like me, you weren't using the *ubuntu* guide linked above, but the upstream guide: https://linuxcontainers.org/lxc/getting-started/ (which is what I was doing -- hence lots of time spinning my wheels).

Thanks for posting this Chris!