1. Verify that you can ping the El Capitan server from the Windows 7 machine.
2. Portscan the El Capitan server, make sure port 445 is responding.
All good? Ok, here's where it gets ugly.
3. Open the command window, CMD.EXE, on Windows. Type 'regedit'.
4. Expand folders:
HKEY_LOCAL_MACHINE
SYSTEM
CurrentControlSet
Control
5. Select the folder 'Lsa' within 'CurrentControlSet'. A list of keys should appear to the right in the Registry Editor application.
6. Select the key called "lmcompatibilitylevel". Choose "Modify" from the Edit menu.
7. Set the "Value data:" field to "3". Click "OK".
8. Quit Registry Editor.
9. Try connecting again.
