This article describes how to transfer a Zemax legacy softkey license when working on an isolated computer without internet access. The steps are the same for all legacy Zemax products.
Note that this is now the only method to transfer a legacy license as the online transfer server was shut down in Jan 2025.
If you are using Ansys-licensed versions of Zemax software, see Ansys Zemax licensing overview and guides.
Authored By Don Dickinson
Introduction
Before proceeding, please read:
This article applies to software licensed via legacy Zemax softkey licenses. This does not apply to any USB license as they come already activated and are "plug and play".
Legacy Zemax softkey licenses include 6-digit alpha-numeric serial numbers beginning with "L" or "T" (e.g. L100000). You can identify your license type using the guide located here: How to identify your legacy Zemax license.
If you are using Ansys-licensed versions of Zemax software, see Ansys Zemax licensing overview and guides.

Transfer a softkey license from/to a machine without internet
This section describes the process for transferring a softkey license from a machine that does not have internet access or to a machine that does not have internet access.
Important notes before beginning
- The license must be activated and working on the machine you are transferring it away from. If the licensed machine was lost, stolen, has the operating system reinstalled or has crashed, the license is lost and subject to the Zemax legacy Licensing Policy.
- The Zemax License Manager or Opticstudio must also be installed on both the source machine and the destination machine before beginning.
- You will need a location accessible to both machines to transfer the license file and Zemax_RUS tool. We suggest a USB storage drive or an internal network share.
- Download the Zemax_RUS utility.
- The Zemax_Rus utility is required to be downloaded to both the machine currently hosting the license (the source machine) and the machine to which you want to transfer the license (the destination machine). The download link is at the top right of this article.
Once you have the Zemax_Rus tool on both machines and all of the above are true, follow the steps below to complete the transfer.
TIP: The term source machine refers to the machine where the license is currently activated. The term destination is the machine you are moving the license to.
Part 1 - Generating an ID file on the destination machine
- Start on the destination machine (where you want to move the license to). Verify that the licensing software is working by opening a web browser and navigating to the http://localhost:1947 (Sentinel Admin Control Center). Your machine does not need internet access to load this page – it is an application that runs on your machine via a web browser. It should go to the help page that looks similar the image below.
If this page opens to an error message, then the Sentinel LDK licensing runtime required to use your OpticStudio license did not install properly. Refer to "How to troubleshoot softkey license issues" "repairing the license runtime" section. Return to this article and move to Step 2 once the Sentinel Admin Control Center is working.

- Open Zemax_RUS utility (The download link is at the top right of this article). Navigate to Transfer License tab. Save a recipient information (.ID) file to your desktop by clicking the "..." button.
We suggest you name the file destination.id to match the steps in this article and click Save. However, the particular file name is not important.

3. Click Collect and Save Information. This will display a notice that the recipient information is stored in the file. Do not skip this step or the transfer process will fail.
Important: Do not change any computer hardware or the Windows computer name / domain on the machine you created the destination.ID file on until after completing the offline transfer process. Doing so may cause the transferred license to be disabled or the process to fail.

Part 2 - Creating the license transfer file on the source machine
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Move or login to the source machine.
- Copy the "Destination.id" file you created above to the source machine.
- Confirm that you are moving the correct license. You need to find the
"key id" by opening the Zemax License Manager application. This is located in the Windows Start menu under either the Zemax Opticstudio, Zemax License Manager.
For License Manager versions dated Nov 2018 or earlier, navigate to the License Information tab. The Key ID is just below the Key serial number .
For License Manager versions dated May 2019 or later, open the View License tab. Click the License Number (such as L100000) to bring up the License Details page and find the key id.
- Verify the key id you want to use says "Local". if it doesn't say local, you are not logged into the machine where the license is activated.
- Verify the license is not in use by closing all instances of Zemax software in the machine.
If you are moving a network license, you also need to make sure there are no open client sessions using the license. You can check which client machines have an open session by opening the Sentinel Admin Control Center @ http://localhost:1947/_int_/sessions.html as described in this article.
TIP: The fastest way to close all client sessions is to disconnect the licensed machine from your network as you cannot force clients to disconnect otherwise. Any client machines that lose access to the license will be able to save their file before quitting.
- Open the Zemax_RUS application.
- Navigate to Transfer License tab and select the Key ID of the license you want to transfer you found in step 6.
- In this example, we are going to transfer license number L101601. So to transfer L101601, select the Key ID 855860311232220694.
- Click the "..." button next to "Read the recipient information file from" and select the “Destination.id” file that you copied from the destination machine. Click Open.

14. Click the “…” button next to "Generate the license transfer file to."
15. Save the file as “TransferFile.h2h” (we use this name in this example, but the particular file name is not important).
Important Tip: If you are transferring more than one license, be sure to give each license a different transfer file name (including the license number is a good way to do this. For example L123456transfer.h2h). DO NOT overwrite one transfer file with another. If you do so, you will have lost the license you overwrote. If it is lost, your license will be subject to the Zemax Licensing Policies.

16. Select Generate License Transfer File. You will see a message asking to confirm that you want to transfer your license away to the destination computer name (Owner-PC in the image below). Click Yes to confirm.

Important Note: Your softkey license is now contained in the "transferfile.h2h" file. Make sure not to lose this file. If it is lost, your license will be subject to the Zemax Licensing Policies. We recommend copying rather than moving the transfer file from the source machine to your transfer media in case it is lost or damaged in transit.
Part 3 - Completing the license transfer on the destination machine
17. Move to the destination machine and copy the generated "TransferFile.h2h" to it.
18. Open the Zemax_RUS tool.
19. Navigate to the Apply License File tab. Select "...." button next to Update File. Browse and select the TransferFile.h2h file. Click Open.
20. Click Apply Update.

21. You should get a message that the update was successfully applied.
To ensure that the license has been transferred successfully and is working, open the Zemax License Manager. Navigate to the License Information or View License tab and confirm the license is in the list. If you will be running OpticStudio or other Zemax software on the destination, open it and verify it recognizes the license as well.
If you have any troubles with this process, see the "Getting help" section below.
Getting help
If you receive any error messages contact support for further help. Please include:
- your license number (such as L000001)
- any error messages
- a screen shot of the Sentinel Keys page located in the Sentinel Admin Control Center.