Comment 8 for bug 436041

Sorry for the delay - day job intruded.

The server event log has nothing near the time in question, and nothing I can relate to Access Denied.
No problem with /dev/sda size - except my geriatric amnesia.
To avoid red herrings, my /etc/hosts file did not have the server name; name resolution must have been used.
Debug level 3 set in client smb.conf but nothing found in /var/log/samba.

I have restarted the client (sadly following an Ubuntu update that included a Samba security fix....) and will recheck the backup and system logs when I go back in.