Virtual Desktops creating 2 desktops for each user

Hi,

I am running 2012 server with Win 8.1 VM's in a Personal collection. I have the system auto assign the desktop for each user. Its been running great for 2 months and now the system is assigning 2 Virtual Desktops for each user. This caused the system to run out of VM's to assign. I tried to delete the Pool and re-created it but it pulled all the VD's back in. My question is 1) Why is it doing this and 2) How can I delete the abandoned desktops without shrinking my pool 3) How do I keep it from happening again.

Thank you for your input,

James