In Version 9 When performing a scan, a machine is skipped with the Error Code: 4 and Status: Machine resolved multiple times; skipping this one.
In version 9.1 the error will show: Machine filtered in its Machine Group.
When scanning a Machine Group, an option is selected in the Scan Only section that one or more machines in the group does not qualify for.
Example: When adding workstations, the option Scan Only Servers is selected.
Uncheck all options in the Scan Only field, or ensure options selected match the machines that are in the list.
Example: Select Scan Only Workstations if workstations are the only machine types in the list.