samba - Jun 2013 - Samba failing irregularly ('Access is denied' in Windows), restarting smbd 'works'

Hi all,

I have been a happy samba user for a few months now. Since last week I have
been a less happy user, however. I am hoping you can help. I probably need
some directions on debugging/log viewing.

I have a samba 3.5.10 server which works fine most of the time (on my
Centos 6.3 machine). Windows (2008 R2) users are using network drives from
this server. I set up winbind which seems to work.

Problems started to happen when I deleted the winbind_idmap file. Somewhere
on a list I saw this was perfectly fine to do. The idmap did rebuild, but
the group-id mismatched (I think someone deleted a user account on the ad
server). I then fixed the group IDs of the files and everything is working
again.

The problem I am having is windows boxes telling me "[sharename] is not
accessible - Access is denied". I don't know how to find the source of
this
problem. I set "log level = 2 winbind:3 auth:3", but I don't know
what to
look for. When this problem occurs, I currently restart smbd and things
work again.

Can someone push me in the right direction?
Thanks,
kl