Hyper-V and "Event ID: 157 - Disk x has been surprise removed"

After posting about Hyper-V and Event ID 58 the other week - I had a number of people ask me about Event ID 157.  They told me that each time they backed up a virtual machine they were seeing this event inside of the virtual machine as well.

At first, I could not figure out why they were seeing this - as I did not see it on my system.  Then I discovered why I was not seeing this - my systems are up-to-date!

We released an update to get rid of this event (KB2958027) - and this was then included in the November 2014 rollup (KB3000850). 

So if you are seeing this event log being filed:

  1. Install these updates!
  2. Or, know that you can safely ignore this message if it is happening when a virtual machine backup is happening.