Here's a posting that we had a few years back that I thought was worth repeating…
How can I tell who is logged into SolidWorks Enterprise PDM?
Answer: SolidWorks Enterprise PDM does not use any fancy license management software, it keeps track of licenses and logged in users inside a SQL database. So, to get a license count, all you have to do is run a user search from Windows Explorer.
When logged into SolidWorks Enterprise PDM go to Tools > Users (if there is no Users pick available, your admin has to turn this on in the Search Card form)
When the search dialog comes up, just make sure the box marked "Show logged in users" is checked and the box marked "Show logged out users" is unchecked.
Next select the search button (upper left corner, looks like a magnifying glass)
A list of all logged in users will display. You can see user information related to those users and you can send them an email by Right-clicking on the user's name and selecting "Send Mail". It will send the mail using the internal notification system or using your normal SMTP server.
For more info, visit www.inflow-tech.com.