Hi @fran,

Looking at this article:

https://support.zemax.com/hc/en-us/articles/6466430529811-FAQ-on-opening-multiple-Opticstudio-instances#:~:text=What%20are%20instances%3F,through%20the%20ZPL%20or%20API.

It seems that if you use a Standard ANSYS license, the number of allowed instances is: N/A. It is up to interpretation, but I think it might actually mean one. Do you use a Standard license?

Take care,

David

Hi Fran,

Perhaps you have one session that is opened but not visible. It can happen in case of a crash, a zombie process. Check your task manager to see if there is not a second Zemax Optics Studio process.

David, I believe the N/A in the table is because there are no such thing as a Zemax Entreprise nor a ANSYS Standard licenses. I would have like to confirm this but I have spent the last 10 minutes in vain trying to find the list of available licenses for OpticsStudio on ANSYS web site.

Oh right, thanks @Ray. Hopefully its just a case of a zombie process!

You should be able to see your license in the windows title, and also the value of the instance number next to it:

Here, this is instance 3 of the Premium version.

You could also check the logs of the license utility in the Help tab

 Press View Logs

You might see some error message in the log files.

Hi Ray,

Thankyou for your quick response.

Here is the License that is shown in my Windows Title Page.

 It is listed as an Enterprise  License with  instance number (21). The Ansys License Utility window shows it as Premium. See below screen shot.

Here is a screen shot of the License Utility .

Here is an excerpt of issues reported by the Log File. The server and port settings are correct because the  server/port settings work for 1 instance

Hello!

The number at the top of Opticstudio isnt meaningful; the instances are not counted there. 

We have recently opened a bug report about some people having troubles opening multiple instances with Ansys licenses. Have you opened a ticket with Zemax support? We can associate you with that bug repoirt. 

Have you already tried adding “localhost” to "Server 1” in the Ansys license Utility? 

Thank you Don, I will check with our IT people to see if they have tried setting “localhost to server 1 in the license utility.

Hello!

You can set the localhost option on your machine from Help > Licens utility in OpticStudio. This is not a setting that requires an admin. 

Did you also open a ticket on this with Zemax support? if not please do so so we can associate you with the bug.