ZCM 11.3.1 on Server 2008 R2
4 Primaries 220 Satellites 6700 workstations

If I look at Device > Workstations > Windows-7 > Prod I have 6664 devices
When I run an inventory report on restrict to all devices in Zenworks Folder = Device > Workstations > Windows-7 > Prod
I get 6572 devices

Is there some way to run a report to get every device?
How can I identify the devices missing from the report?
can I do to something to those devices to make them appear on future reports?

thanks
Greg K