Windows 7: Cannot reconnect mapped drives

Hi all, I apologise if this question has been beaten to a pulp, I just want a 'once and for all' answer. After many google searches, I have yet to find one.

I have a windows 7 pc that is part of an office network along with about 5 other machines. They are all supposed to connect to a server via network mapping of the server's shared folder. (In this case the mapping is Z:\\pi-server\data and the server is running 2008 R2 on a workgroup). Upon reboot, all systems but one will remap to this drive with no problem.

The one machine will always boot up with the message 'Windows could not reconnect network drives' The mapping is showing in windows explorer but there is a red 'x' icon showing the connection is lost. When I click on it, it prompts for windows credentials, which I enter and then it remaps with no problems. However upon next boot the same thing happens again. No matter what I try I cannot get the system to retain the credentials.

What I have tried so far:

1. Ensuring that there is a match of user names and passwords on the server and workstation.
2. Deleting the mapping and re-adding it.
3. Running a batch file to delay the mapping in order for windows to finish connecting the network first.

I would like to be able to browse to the network folder via network discovery through the workgroup but this particular machine does not have the server show up in the network listing (all other machines do show the server). Plus when pinging the server, it insists on responding with ipv6 unless I force a v4 ping...not sure it's relevant but I'm trying to get all information here.

I have encountered this issue several times before with no resolution (except at home when we had to replace our server--then the mapping magically worked!) Please let me know if you have a definite fix for this issue.

This seems to be an ongoing issue with Windows 7 machines and there are many TechNet threads that talk about the issue, many of those threads have working solutions for the problem but it's hard to say which solution would be best in your particular case.

Windows 7 Pro PC's won't automatically map network drives at reboot