virtualbox.org

I'm having an issue with a user who is running OSX and has two Windows 7 virtual guests. The virtuals are natted to the host, not bridged.

The issue is that his machine is broadcasting BPDUs and is causing the port to go disabled on the switch due to a spanning tree event. I see conflicts between XP guests on virtualbox but I don't see anything for Windows 7. Other users on Windows hosts that have Windows guests are not having this issue. It SEEMS to be specific to Windows 7 run in virtualbox on an OSX host.

Any ideas?

Windows sending BDPU? that seems very unlikely, unless you configured it specifily yourself, and you would require a third party anyway.
Just doesn't make sense to me what you are saying here I am afraid..