The Spectrum Users group is created by default at the time of Spectrum installation on Windows. This is the group that owns the Spectrum install directory.
DX NetOps Spectrum installed on Windows
The Spectrum users who are responsible for performing Administrative tasks on the application should be part of this group to grant them full access. This group is needed for the application to run properly as most of the processes need full access at the Operating System level. This group should not be deleted.