Clustered SAN volumes not showing up in Windows Explorer

I have seen this also in the past when I deployed a failover cluster. One time I fixed it by executing the following PowerShell command: Remove-ClusterNode After that I executed the following command to clear the configuration on the node: Clear-ClusterNode You have to start the Windows Powershell Modules from the Administrative Tools otherwise these commands won't work. After that I was able to succesful join it to the cluster

If these commands don't work, I'm afraid you have to reinstall the operating system on each node of the cluster.

You should map the drive from within your administrative CMD session instead, as it is using a different user context (the one of the administrative user obviously) and thus has no access to the environment of your "regular" user. From http://msdn.microsoft.com/en-us/library/windows/desktop/ms685143(v=vs.85).aspx :

Drive letters are not global to the system. Each logon session receives its own set of drive letters from A to Z. Therefore, redirected drives cannot be shared between processes running under different user accounts. Moreover, a service (or any process running within its own logon session) cannot access the drive letters that were established within a different logon session.

Just issue

net use z: \\server\unc\path

to establish the mapping in your cmd session before executing whatever you want to be done with it.