$(subj), it appears to be what root user is denied by default for all of the shares. I'm trying to reproduce Windows administrative share.
You should be putting up your smb.conf so that we can actually assess the problem. Anyway here's a hint:
invalid users = root
is part of the default smb.conf.
Well then. Is root a valid smbuser, yet? Then try explicitly allowing root :
valid users = root
And try something like this:
[config] comment = Admin Config Share - Whatever path = / valid users = someusers, somegroup force user = root force group = root admin users = someusers, somegroup writeable = Yes
if you can't access two users, one for a regular user and the other for a root, you need to alias the netbios in smb.conf file so that windows sees them as two servers. Then access each with a different user id. You may also add to the windows' host file the same server's ip with different names. The issue is with Windows that can only allow one user at a time, thus cannot access as a root.