I'm trying to filter out machines that don't have anything in the Last Checked In field, but not sure what criteria i should use... should I just create a static group and manually check those machines off ,and add it as a not a member of group?
Just came across this issue as well. I usually have a couple of Smart Group that look for machines that haven't reported in for some time. Sometimes we even use this data to purge machines that are no longer around. I recently noticed I had a bunch of machines that don't get found by these groups because the check in date is blank.