You should probably skip this and use rsync!
If you get this: SMB Signature verification failed on incoming packet!
Try the following in the smb.conf global section and restart samba:
client signing = no client use spnego = no
Lets say you need to back up a Windows 7 home version....
Lets just say the user won't probably be a candidate to install rsync.
Here is what you do:
Have them set up a share with a user, and assign read rights to that user to the backup share.
Set up dns (locally via hosts if you have to) to match the machine name.
Make sure the name exactly matches or Win 7 will punt on the connection.
Even if the hostname has a hyphen!
Update Samba if things still don't work.
If you find there are share permissions on the Users directory:
You can give this reg key a shot. Warning it could break things and make you un-secure:
If you get permission denied errors, swap the share for the hidden default c$ share and try again.
If you are backing up Windows via SMB, don't forget the control panel -> folder options
To set "Show hidden files, folders, and drives"