I have a small network. I have one small server running Windows 2000 Pro SP4 (yeah, I know but it works very well otherwise). I have multiple computers I use to access the Windows 2000 Pro server with multiple Windows operating systems including XP Home, XP Pro, Vista Home, and even a windows 98 machine (don't ask).
Everything was working great except the Windows 7 machine (of course). In fact, the windows 7 machine was working fine until yesterday.
When I double click on my mapped network drive, it asks me for a Network username and password and says:
Enter Network Password
Enter Your Password to connect to: Server (name of the server is Server)
LAPTOP\Jerry (Laptop is the name of the computer and Jerry is the username. Everything is case insensitive but I entered it case sensitive anyways).
Logon failure: unknown user name or bad password.
I hear this is very common. I have user names and passwords set up in the Windows 2000 Pro server which match the Windows log in Username and password. This is true for all users across the network and everything works great (if I remove a user, they can no longer access the server).
I have tried:
Disabling the HomeGroup
Setting the advanced share settings to on or off depending on the options (as free and least secure I can get).
Disabling Firewalls (on both ends).
Guest Account on the Windows 7 Machine is off.
Added new user with same credentials as a known working user/password to the Windows 7 machine and tried to access the server with the same results.
Please note: I have NOT changed a thing on the Server end of things. I am not the user of the Windows 7 machine so i am unsure what exactly happened; however, I am told (and I believe) that the user did nothing to provoke this). The user account is still active. I can access the server on a different machine using his log in.
The windows 7 machine can see other computers in the network and view their files.
Solved (at least for me)!
Windows sent out an update removing a level of security check. None the less, here is the solution that worked for me.
In Windows 7, click Start (or tap the windows button).
Type regedit and hit Enter.
Open the following path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
If it does not already exist, create a DWORD value and call it LmCompatibilityLevel
Set the value to 1