Enable Administrative Shares (C$, etc)

1. Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
2. On the Edit menu, point to New, and then click DWORD (32-bit) Value.
3. Type LocalAccountTokenFilterPolicy to name the new entry, and then press Enter.
4. Right-click LocalAccountTokenFilterPolicy, and then click Modify.
5. In the Value data box, type 1, and then click OK.
6. No reboot necessary.

From an administrative command prompt, you can simply run this instead:

reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" /v LocalAccountTokenFilterPolicy /t REG_DWORD /d 1