[Samba] Samba 3.0 PDC + XP + roaming profile = big, strange mistery of sorts

[Bruno Ferreira]

Please bear with me as this is quite a complicated problem which has 
eluded me for days now...

I recently upgraded a Samba 2.2 PDC to Samba 3.0 [3.0.20a as of now]. 
After upgrading, I had problems with two XP machines, among 16 of them. 
One of them didn't validate the domain users correctly. That was 
immediately taken care of by having said machine leave and re-join the 
domain. Nothing else was done here. As for the other machine...

After the upgrade, when logging in to the domain in that machine, it 
said that the machine account didn't exist. Except it did :/ . I deleted 
the machine account and recreated it, having it leave and re-join the 
domain in the process.

Now, here comes the real problem:


- The user can now log on, except that all of Windows' settings were 
gone, and back to the default.
- The profile *was* downloaded to the local machine, and all the files 
were present, but it acted as if the registry somehow wasn't present.
- Even after redoing some configuration, on logging off, even though 
some files in the roaming profile were updated in the server (NTUSER.DAT 
included), logging in again produced the same problem.
- Deleted all local copies of the profile. Same thing. I always reverted 
to a known-good copy of the profile between tests.
- Checked permissions on the local copy of the profile. Permissions were 
OK, the domain user had the full control over his local profile directory.
- Out of spite, said machine was reformatted. Problem repeated itself 
and remained. Note: said machine has no different configuration from any 
other; the user also has a regular roaming profile like anyone else.


I'm now out of a total loss of ideas. jerry @ freenode (Jeremy Allison?) 
even helped out a bit, but I couldn't get anywhere, even after trying 
lots of things.

Now, something tells me that this has something to do with domain SIDs 
or the like (of which I have little knowledge, I know what they are, but 
I'm not savvy enough to go around investigating them). I even deleted 
secrets.tdb so that Samba would recreate it, which wasn't a smart move, 
as I came to learn, but will most likely come to no harm (I hope).


I'd like to know two things, and I'll take any suggestions that I can get.

a) The cause, so that I know why this happens, and I can avoid it later.
b) The solution, obviously. I've been delaying other work because of 
this and my brain now feels like jelly because of bashing my head 
against the table :(


Hopeful for some insight on this,

Bruno Ferreira