Matt Riggins writes:

I upgraded a machine in my office to Vista to get a feel for the OS, how it works, etc.

I use both a variety of Windows and Mac boxes and the first thing I noticed after upgrading to Vista was that I was unable to connect to the Mac’s SMB File Sharing. Typically in the windows address bar under XP pro I would type:

\\IP Address\username (the username being the short name on the OS X user account)

It would prompt me for a username and password, which I would type. (The os x username/pw) The share would come up (the user’s folder) and I was done.

This did not work in Vista. It would ask me for the username / password, but typing it didn’t work.

I googled it and came across this great post:

http://www.macfixit.com/article.php?story=20070226082237597

There are a couple of things to try on this post. The first being from Vista using the command line trying to login using IPAddressUsername together. I tried that, with no luck. The 2nd step is a registry edit in vista. I make this change and it now allows me to share to OS X again:

1. “Click Windows Visa Start Orb
2. In search box, type “regedit” and return
3. Once regedit opens, click File -> export to make a backup copy
4. Navigate to Computer HKEYLOCALMACHINE SYSTEM CurrentControlSet Control Lsa.
5. In the right pane, right-click the “LmCompatibilityLevel” key and select “modify”
6. Change the value from 3 to 1
7. Exit regedit and you should now be able to properly authenticate to your Mac OS X (or other Samba) share.”

Matt Riggins

2010-01-10 Update:

I ran into this very issue myself yesterday on a friend’s netbook and found my own post from Matt. I wanted to see if there was a non-regedit solution by now and there is, so as an alternate solution (copied here in case that site goes down):

1. Click Start.
2. Type secpol.msc in the search box and press Enter.
3. Windows Vista will display a warning message; click Continue.
4. Windows Vista’s Local Security Policy console will appear. Highlight Local Policies.
5. Double-click Security Options.
6. Scroll down to the Network Security: LAN Manager Authentication Level policy entry and double-click it.
7. Change the value from the default setting of Send MTLMv2 Response Only to Send LM & NTLM — Use NTLMv2 Session Security If Negotiated, then click OK.
8. Close the Local Security Policy console.