Cannot clone any template - 'VM PV drivers still in use'

Created VMs with several versions of windows, installed vm tools, sysrepped and converted to template. Now some time later, any attempt to create a new vm from those templates results in the error 'VM PV drivers still in use'. I'm willing to attach a xenserver status report, just let me know what content items you want included.

I couldn't find much on the error through an internet search and I didn't find anything of immediate interest in logs, except a repitition of this error message.