Since installing RC12 with the auto-updater I have not been able to open our solution with more than one user. The second user in either fails to retrieve data or locks up, or both. The Servoy-Admin shows 5 approved licenses.
It is possible that the experimentation that I was doing with record locking may have had an impact on things. I just removed the method that was placing a lock on the contacts table whenever a field was being edited, and then I was able to open more than one client. However, there may be something else going on. My PC is currently acting as if it is downloading a Windows operating system update. So I will wait and then test some more tomorrow morning.