Make sure that "File sharing" / "Bestanden delen" is enabled:



Default admin shares

The default admin shares (c$ & d$) are no longer accessible from a remote machine by default (they are in a domain, not in a workgroup!):

 [[file://\\...\c$][\\...\c$]] is not accessible. You might not have permission to use this network 
resource. Contact the administrator of this server to find out if you have access permissions.

Multiple connections to a server or shared resource by the same user, using more than one 
user name, are not allowed. Disconnect all previous connections to the server or shared 
resource and try again.

The following register edit solves this problem:

Computer > HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion > Policies > System:

DWORD value
LocalAccountTokenFilterPolicy 1


admin shares administrative shares