Samba Password Expires
I’ve had this problem with an old install of samba, after upgrading a while back it keep expiring the password for users. I could find anything in the docs or howtos for Samba. Today I managed to figure the right google search and discovered this single page: [Samba] Password expires.
This was fixed in eitehr beta3 or rc1. You need to stop smbd, remove the account_policy.tdb, and restart smbd. The new default is to set the must change password field to something like NT_TIME_MAX (0x7fff ffff IIRC).
Update (08/04/05): Also you can tweak account policy numbers with pdbedit. [ See passdb. ]