Virtual standby/export is failing with error: "System.Net.Sockets.SocketException: Only one usage of each socket address is normally permitted" (4040618)

When performing a virtual standby/export, the process may fail in the middle, leaving exported VM in the corrupt state. Error is: System.Net.Sockets.SocketException: Only one usage of each socket address (protocol/network address/port) is normally permitted

Subsequent attempts to perform a virtual export are also failing, but may produce a random VM error.

The issue is caused by the exhaustion of TCP/IP sockets on the Core server. It is possible this is from third-party applications on the core server or if the core is busy doing multiple transfers, replications, and exports for many protected machines. TCP sockets are being exhausted because of the default TCP socket wait timeout, which is 240 sec.

The issue is known as defect D-34828.

This defect is resolved in the version 6.1 release, but this is also an environmental issue where all the sockets are used up.

To resolve the issue:

1. Ensure the core build on a build later than version 6.1.x.
2. Delete the partially exported VM on the hypervisor.
3. Reduce the value of TcpTimedWaitDelay to 60 according to this Microsoft article: https://technet.microsoft.com/en-us/library/cc938217.aspx or https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-2000-server/cc938217(v=technet.10) Otherwise, create the registry key if one does not already exist.  It's possible to reduce the value even more if the issue is not resolved.
4. Restart the Core server.