OK.  After rebooting, Next time, don't set it offline.  Just close any explorer windows, or anything that accesses it.  Then logout via iSCSI initiator.   See if that changes anything.    If not, then reboot, and try deleteing the partition before logging out.   There's no need to set offline in Disk Manager first.  Otherwise try a different OS version to mount the replica.   Window7, for example. 
Hi, I have been utilizing SAN Replication and cloning it to my local machine using iSCSI Initiator.  After I'm done with the clone, I disconnect it from iSCSI Initiator.  Then set it offline and delete the volume.   I've noticed that I have a ghost drive that used to be the cloned volume.  There is nothing I can do to get rid of it and release the drive letter.  It doesn't show up in Disk Management and diskpart.   Is there a way to delete the ghost drive?  Am I disconnecting from the replica properly? Thank you.
SAN Replica Clones - Ghost Drive