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Windows Vista NTLM issue

July 18, 2011 • Customer Services       

Synopsis

Article

Problems with NTLM auth (SP1 vista)
- Microsoft have moved the goalposts. NTLM-2 has been implemented. To downgrade, follow these steps:
The solution is to force Windows Vista to use the older encryption methods. To do that, follow these steps:

Users of Windows Vista Home Basic and Home Premium
CAUTION: Improperly modifying the registry can harm your system.
1. Click start
2. Type: regedit
3. Press enter
4. In the left, expand these folders: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\
5. In the left, click on the folder named: Lsa
6. In the right, double-click "LmCompatibilityLevel"
7. Type the number 1 and press enter
8. Restart your computer

Users of Windows Vista Business, Enterprise, and Ultimate
1. Click Start
2. Click Control Panel
3. Click System and Maintenance
4. Click Administrative Tools
5. Double-Click Local Security Policy
6. In the left pane, click the triangle next to Local Policy
7. In the left pane, click Security Options
8. In the right pane near the bottom, double-click "Network security: LAN manager authentication level"
9. Click the drop-down box, and click "Send LM & NTLM - use NTLMv2 session security if negotiated"
10. Click OK

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