Hyper-V Agentless Transfer fails with error "Object reference not set to an instance of an object." (hypervMachineTransfer/clearBitmaps) after moving VM to another node (4040928)

Moving an agentless protected virtual machine from a Hyper-V node to another, causes the next transfer to fail with the error "Object reference not set to an instance of an object."

The transfer is failing on the latest step during "cleaning bitmaps".

The issue has been identified as defect RR-102148.

The issue has been reproduced when "Maximum concurrent transfers from a single Hyper-V host" does not have the recommended value.

In addition, you must verify that the cluster's environment is stable, for example that there is no cluster related error in the windows event logs (e.g. Event ID 1135: which indicates that one or more Cluster node was removed from the active failover cluster membership, Event ID 1205:  One or more resources may be in a failed state. This may impact the availability of the clustered service or application).

Ensure that there is no network related problem, and that every node resolves by its hostname.

Workaround:

Change "Maximum concurrent transfers from a single Hyper-V host" value to 1.  

1. Select the Hyper-V Cluster from protected machines.
2. Got to Settings.
3. Change value in the Transfer Queue option.