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