Allegedly, on or about 08 June 2013, Joe Zeff sent:
Then, when you create your username during firstboot, you use the same one as you did before and tell the program to use the same folder and to leave the contents intact.
If you have more than one user, then either make sure that the newly recreated users have the same UID and GID, or chown recursively their homespaces to their new IDs.
Whenever I set up a system, I set up one or two test users when I set up my own account. It makes fault finding, and restoring a stuffed account, an awful lot easier when you have a spare account ready and waiting.