You cannot access a shared folder that is located on a Windows 2000 or Windows 98-based computer from a Windows 7-based computer

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this issue, enable NTLMv2 authentication on the Windows 2000- or the Windows 98-based computer. To do this, follow these steps:

1. Start Registry Editor. To do this, click Start, click Run, type Regedit, and then press ENTER.
2. Locate and then click following registry subkey:
   
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA
3. Locate the LmCompatibilityLevel registry value.
   
   
   
   If the registry value is not present, follow these steps to create it:
   1. Select the registry subkey that is listed in step 2.
   2. On the Edit menu, point to New, and then click DWORD Value.
   3. Type LmCompatibilityLevel, and then press ENTER.
4. Set the DWORD value to 1. To do this, click Modify on the Edit menu, type 1 in the Value data box, and then click OK.
   
5. Exit Registry Editor, and then restart the computer.
   

For more information how to enable NTLMv2 authentication, click the following article number to view the article in the Microsoft Knowledge Base:

239869 How to enable NTLM 2 authentication

Note Samba 2.x does not support NTLMv2 authentication. Therefore, you may encounter similar issues when you try to access shared folders that are located on Samba systems from a Windows 7-based computer. To work around this issue, follow these steps on the Windows 7-based computer:

1. Start Registry Editor. To do this, click Start, type Regedit in the Search programs and files box, and then press ENTER.
2. Locate and then click following registry subkey:
   
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA
3. Locate the LmCompatibilityLevel registry value.
   
   
   
   If the registry value is not present, follow these steps to create it:
   1. Select the registry subkey that is listed in step 2.
   2. On the Edit menu, point to New, and then click DWORD Value.
   3. Type LmCompatibilityLevel, and then press ENTER.
4. Set the DWORD value to 1. To do this, click Modify on the Edit menu, type 1 in the Value data box, and then click OK.
   
5. Exit Registry Editor and restart the computer.
   

Warning This workaround may make a computer or a network more vulnerable to attack by malicious users or by malicious software such as viruses. We do not recommend this workaround but are providing this information so that you can implement this workaround at your own discretion. Use this workaround at your own risk.