Loss of accounts with f11 update

[Bruno Wolff III]

On Sat, Apr 04, 2009 at 07:47:26 -0500,
  Mike Chambers <mike at miketc.net> wrote:
> 
> I ran into this during the middle of devel between alpha and beta.  What
> I found out, was  when doing any kind of major update like above, just
> boot into run level 3 first and then run the upgrade.  That way X or
> anything else doesn't try to restart or anything and interrupt the
> update and cause problems like you experienced.

Other options for when things are really hosed are to try booting to run
level 1 or using a rescue disk / image to boot.