We recently upgraded our machines. The old ones were Windows XP running on 32-bit dual core processors. The new ones are with Core-i7 processors and had Windows 7 Professional (64 bit) preinstalled.
In our existing setup, we have one windows 2008 machine and many windows XP machines. The PCs are connected in a Workgroup, and the server is used mainly as a DHCP server, internet access and for common file sharing. There were no issues till now accessing the Windows 2008 Server from the existing Windows XP machines.
Now, in the new Windows 7 machines we found a peculiar problem. Everything worked as expected, except that we are not able to access the shared folders on windows 2008 server even after providing the correct credentials. They were able to connect to everyone else on the network properly (i.e. other new Windows7 machines as well as the existing windows XP machines). The internet was also accessible and server showed in their network lists too. But the shared folders on server were inaccessible even after providing the correct usernames and passwords.
After searching on the internet about this problem, I was able to resolve it as follows:
1. Launch the Local Security Policy console by clicking Start button and then typing secpol.msc in the search box.
2. In the Local Security Policy window, left pane, expand Local Policies, and then Security Options. Then in the right pane locate the entry Network Security: LAN Manager authentication level
3. Double click that entry to open its properties.
In the Properties window, set the dropdown to Send LM & NTLM – use NTLMv2 session security if negotiated.
Click OK to save and exit.
4. Reboot the system if required. Then verify that you are able to access the shared folders on the windows 2008 machine (after providing appropriate username and password).
I had to waste a day figuring out this thing. I hope this tip saves someone’s day!