This tidbit of information may be known to many of you, especially if you work with NetApp storage, but I’m posting it anyway as a reminder to myself.
After configuring a couple Windows 2008 servers as a failover cluster using a file share witness quorum, I enabled iSCSI and installed SnapDrive on NodeA. An iSCSI connection to the NetApp storage was established, but when attempting to use SnapDrive to add new disks, I received the message: “SnapDrive error: Class not registered“.
To correct, SnapDrive had to be installed on NodeB of the cluster. Once installed on both servers, I could use SnapDrive to add disks with no problems.
ballblog 
thanks for the info!
Usefull info, thanks! saved me some time 🙂
SnapDrive error: Class not registered
On Snap drive 6.2 Windows 2008 R2 install of Exchange 2010.
Even though the two nodes are not clustered in Ex 2010 there's a thing called DAG “database availability Group”
in order for snap drive to work it needs to be on BOTH nodes.
Several days ago I was at the Inet and observed good tool, which might assist in this issue just like me – fix microsoft exchange.
So I have 8 2010 Exchange Servers four in one data center on one vCenter and four in another data center on a different vcenter Do I need Snap Drive installed and configured on All the Exchange Server per data center to use Snap drive and not get this error?