Bootcamp Windows 7 external mic
I have the same issue.  I found this thread which basically states, it is a known bug with Bootcamp.  There has been no fix for like 4-5 years:

https://discussions.apple.com/thread/3369017?start=15&amp;tstart=0

I downloaded the latest version of bootcamp (5.1) to no avail :(

If you check the version of Bootcamp you are running (right click on the icon in the taskbar and click About Bootcamp) to see if you are running the latest.

Turns out I was running 4.0 and the latest for my laptop is 5.1.5621 and found here:

https://discussions.apple.com/thread/3369017?start=15&amp;tstart=0