Windows Server 2012: Error Event 12, Hyper-V-VmSwitch

Since migrating to Server 2012 as a VM host, I have experienced this error:

Log Name:      System
Source:        Microsoft-Windows-Hyper-V-VmSwitch
Date:          12-Dec-12 9:40:44 AM
Event ID:      12
Task Category: (1007)
Level:         Error
Keywords:      
User:          SYSTEM
Computer:      MSN-ENTERPRISE.MSNInternational.local
Description:
Failed to update configuration for port B46A61B4-F53D-481A-9A7F-5E49F53A4668 (Friendly Name: b46a61b4-f53d-481a-9a7f-5e49f53a4668) on switch 24A1C522-D467-4334-A8B3-158C44F0FAD7 (Friendly Name: MSN International), status = An attempt has been made to remove a file or directory that cannot be deleted..
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Hyper-V-VmSwitch" Guid="{67DC0D66-3695-47C0-9642-33F76F7BD7AD}" />
    <EventID>12</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>1007</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2012-12-12T09:40:44.667198200Z" />
    <EventRecordID>86569</EventRecordID>
    <Correlation />
    <Execution ProcessID="4480" ThreadID="6504" />
    <Channel>System</Channel>
    <Computer>MSN-ENTERPRISE.MSNInternational.local</Computer>
    <Security UserID="S-1-5-18" />
  </System>
  <EventData>
    <Data Name="Status">3221225761</Data>
    <Data Name="PortNameLen">36</Data>
    <Data Name="PortName">B46A61B4-F53D-481A-9A7F-5E49F53A4668</Data>
    <Data Name="PortFNameLen">36</Data>
    <Data Name="PortFName">b46a61b4-f53d-481a-9a7f-5e49f53a4668</Data>
    <Data Name="SwitchNameLen">36</Data>
    <Data Name="SwitchName">24A1C522-D467-4334-A8B3-158C44F0FAD7</Data>
    <Data Name="SwitchFNameLen">17</Data>
    <Data Name="SwitchFName">MSN International</Data>
    <Data Name="UniqueEvent">1</Data>
  </EventData>
</Event>

Any advice will be gratefully received, as there appears to be no other KB entries. 

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Paul.B