I recently found out how frustrating it can be just to simply push out a mapped drive. Here is what I saw and how I fixed it.

I needed a GPO enabled “X:\” drive map to update the existing locally defined X:\ drives on the Win7 PCs. It used the logged in AD user to attach to the share, this worked without an issue. The second share, using the Y:\ didn’t go so easily. It needed to attach to a Samba server, authenticating as a user located on the Samba server. Well, that’s what the section “Connect as” is used for, right? Well yes, but becareful not to select “Reconnect” if you do, you will find yourself in a situation that the drive updates but will not connect. From what I’ve read online this is due to the drive mount information being stored in the user’s profile, but without the password..so it will fail.

I setup the drive map via the Group Policy Management Editor at the key “User Configuration -> Preferences -> Windows Settings -> Drive Maps”. The drives need to be setup as either a “update” or a “replace”. Check out the settings below, during my tests this is what I found worked. The main thing to avoid is, do not select “reconnect” when using the replace action.
Right click, select New -> Mapped Drive

MAPPED DRIVE X:

General Tab

Action = Update (this option works great as long as you are passing NTLM auth a.k.a. not using the Connect as section) If the drive will not reconnect after a user login (red X) then I prefer to use the Replace method below.
Location = \\fileserver1\sharename1
Leave Reconnect unchecked!
Label as = mainshare
Existing = X:
Do not use Connect as to specify another user, if you need this, use replace
Hide/Show this drive = Show this drive

Common Tab

Select Run in Logged-on user’s security context, to update an existing drive.
(optional) Item level targeting, choose Security Group and choose group that should get the drive mapping

MAPPED DRIVE Y:

General Tab

Action = Replace (use this to do a rip-and-replace of the existing drive)
Location = \\fileserver1\sharename2
Leave Reconnect unchecked!
Label as = secondshare
Existing = Y:
If you need to connect as a different user, in the Connect as section (to use a local Samba user on the fileserver) type

User name = fileserver1\user1
Password =
Confirm Password =

Hide/Show this drive = Show this drive

Common Tab

Do not Select Run in Logged-on user’s security context, to update an existing drive. The drive cannot be removed and recreated if this is selected
(optional) Item level targeting, choose Security Group and choose group that should get the drive mapping.