For security reasons the built-in admin$ family of hidden shares has been disabled in Windows 8.

The situation: you try to connect to a network machine via a hidden share such as c$ or admin$ (\\ MachineName \ c$), error messages include:

• Access is denied.
• The specified username is invalid.
• You may not have permission to use this network share.

Solutions for Access is Denied to Administrative Shares

1. One solution may be to accept the situation and abandon your attempt to connect via C$.  You could try remote desktop instead.  I say this not because the challenge is too difficult, but because the default is the securest configuration for remote user account control (UAC).  Once you enable these hidden admin$ shares then your machine can be attacked by hackers.  Indeed, that is why Microsoft removed this capability, even though it was popular with XP and Windows 98 users.
2. If you really must find a solution to the Windows 8 'Access is denied' message then try leaving the Homegroup.
3. If that does not work then Launch Regedit and adjust Remote User Account Control (UAC) settings.

Use Regedit to Create LocalAccountTokenFilterPolicy Value

Type Regedit in the Search dialog box, best right-click the executable and 'Run as administrator'.

Once Regedit launches navigate to this path:

HKLM\SOFTWARE\Microsoft\Windows

  CurrentVersion\Policies\System (See screenshot below)

Windows 8 Registry Editor

Once you ar at this folder in the registry:
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System

Notes: The text book says create a new DWORD value called LocalAccountTokenFilterPolicy

What I did was create a QWORD (64-bit) called LocalAccountTokenFilterPolicy, that worked for me when the DWORD would not allow access to my 64-bit machine.

In either case, set the value to numeric 1 (meaning on), remember to click OK.

Mostly, the LocalAccountTokenFilterPolicy value gets created before you have a chance to set thedata value; no problem, just double-click and modify the data from 0 to 1.

Firewall: While I made the connection with the firewall ON.  If you cannot get this LocalAccountTokenFilterPolicy registry hack to work try adding File and Printer Sharing to the firewall's Allowed Programs.

The Default Remote Security Situation in Windows 8 and Windows 7

Even if a user is a member of the local administrators group on the remote target, by default, they cannot connect as a full administrator. The user has no elevation potential on the remotecomputer; thus if the user wants to administer the workstation with a Security Account Manager (SAM) account, it's best to logon using Remote Desktop.  However, as discussed above, you could try creating LocalAccountTokenFilterPolicy.