Custom Disk Resource displayed with ‘?’ icon in Fail Over Cluster Manager on Windows 2008 R2 Servers

 You might see your custom storage class resource appears with a ‘?’ icon on Windows 2008 R2 Fail Over Cluster as shown in the following picture: 

The disk icon with ‘?’ mark may mislead the developers and end users of the resource DLL into thinking that the resource is not recognized or not loaded properly in the Fail Over Cluster Manager. 

Any custom resource disk added in cluster will be displayed with icon " ? " on it. The user may think that this is some kind of problem with the disk by seeing that "?" in the icon but actually it is not a problem but just an icon to represent a custom resource disk and isolate it from the Physical disk resource.