1. Launch regedit from Start Search box.
2. Find the following branch.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

3. Create a DWORD key under Lsa and set:

Name: LmCompatibilityLevel
Value: 1

4. Restart.

來源： http://social.technet.microsoft.com...3c-3480ecab5505