If you need to check how many users are logged into your Genie database, you can do this from either a Genie Client app or the Genie Server at any time.
On Genie Client, navigate to File > Maintenance & Reports and click the Server Admin Window button in the bottom-right.
Within the window that appears, the number of users currently logged in will show in brackets on the Users tab at the top.
Click into the Users tab to see the names and more details of currently logged in users.
If you are on the server machine and your Genie Server is running as an application (i.e. not a service), you can navigate to Window > Administration if your server admin window isn't open already.