Floating license not returned or checked back into the license server

Silly question - but does a licence server register when you close the FDTD designer. We have a central licence server here which we are set up to link to - but I seem to have caused some problems for the other users by opening several designer windows to run simulations. However - even after I close down the applications, it seems like the floating licences don’t get ruturned to the server - so people are still locked out. Surely there should be some return of the licences? Or is there something which needs to be reconfigured.


If you are using the latest version of Lumerical FlexLM, the license should be returned/checkin after 4 hours of inactivity.

Otherwise to instantly release the “stuck” licenses, please ReStart(Stop/Start) FlexLM.


Sometimes the application is frozen/hangs and is still running in the background. Be sure to manually close the applications. Check the task manager on windows or running processes in Linux and kill them if they are still running.