I have upgraded my WinForms project to the latest version, as shown in the attached file.
When running the application inside the VS 2022, a dialog box shows with no license.
I tried the suggested resolution from:
https://docs.telerik.com/devtools/winforms/licensing/license-key#downloading-the-license-key
I also downloaded the latest license from my account.
Nothing resolved the problem.
Can you help, please?
Note: My subscription will expire by 20 Sep 2025
1 Answer, 1 is accepted
Hello, Ahmed,
With our latest 2025 Q2 release, UI components from the Telerik UI for .NET WinForms library require activation through a license key.
You said that you already downloaded the License Key successfully from your account. Now, you also need to get the Telerik.Licensing NuGet package from the NuGet Package Manager. It will automatically add a reference to Telerik.Licensing.Runtime dll in your project, which is required to activate Telerik controls.
The exact steps how to activate our controls are described here: Activating the Telerik UI for .NET WinForms Components.
Once you set up the license key and add a reference to Telerik.Licensing.Runtime, you are not supposed to receive licensing messages or warnings.
Please follow the suggested steps, and let me know if you have further issues.
Regards,
Nadya | Tech Support Engineer
Progress Telerik
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Rank 1
Thank you ver much Nadya.
Issue resolved after installing Telerik.Licensing and referencing the Telerik.Licensing.Runtime.
Rank 2
Bronze
Iron
Iron
Hello, I had the same problem and resolved it by installing Telerik Licensing NuGet, it's ok on my notebook now. But when I copied the release project binaries to production machine, dialog with missing license is back again. Should I copy also something else than this?
Hello, Marian,
While you have an active license key and the project runs on your development machine, you should be able to run it on other machines as well. If you copy the whole project binaries output together with the exe file on the production machine, a licensing message is not expected to appear. Can you clarify which files you copied? From the picture, I can see only Telerik dlls.
Note, the license key is only verified at build time. Meaning, after a project has been compiled, the licensing key is consumed. The application that has already been built and is running in production will not be affected.
I hope this information makes it clearer. I can also share the related FAQ documentation, as it may provide further useful clarifications.
Please let me know if you need further assistance and I will help to you.
Rank 2
Bronze
Iron
Iron
Hello, Mariam,
Thank you for the demo project.
In every project were you use RadControls or reference them from your library projects, you should download the Telerik.Licensing NuGet package. As in your demo project, you should have the Telerik.Licensing NuGet in TelerikLicenseTestLib, TelerikLicenseTestSub, and also in the main project TelerikLicenseTest2.
It is not necessary to download any other dummy references, only the Telerik.Licensing NuGet. I installed the NuGet directly in your main TelerikLicenseTest2 project, and it compiles with no errors on my side, and no watermark appears on the forms.
If you have further difficulties with the licensing, feel free to submit a separate ticket from your Telerik account, and we will continue our discussion there regarding your special case. Thank you for your understanding.
Please let me know if I can assist you further.
Rank 2
Bronze
Iron
Iron
Hm, so I don't know why, but when I remove reference to Telerik.Common in main project, I see this in build window. But I see also TelerikCommon reference in your screenshot.
And when I click on one of those two buttons, I see license error:
But it's not a problem for me now, if I know how to solve it, it's not so problem to add reference to some Telerik also to main program. It's not a reason to submit support ticket. It's little bit annoying to add NuGet package to all programs using that library, I would expect it's enough to do it in that library, but ok.
Btw. maybe you should add information about this also to that FAQ on new licensing. Maybe it's not so standard case to use Telerik only in library and not in main program, but I spent some time on this to find it out.
Rank 2
Bronze
Iron
Iron
Hello, Marian,
I was able to reproduce the case that you described and have already raised it to our licensing team for further investigation. For now, you can continue using Telerik.Common dll in the main project, as you found out, so that you can continue your work in the project. However, this case should be further discussed to handle such cases with referencing projects as well.
As to your last question " what to do, if I make a library using Telerik components and give it to another developer, who doesn't even have Telerik license? Or if I sell my library to customers? Or Telerik licensing doesn't officially support this case?"
We do officially support such cases. You described two different cases - using the same library from another developer, AND selling the library to customers. The license key that activates is user-specific.
Each developer who is currently working on the project must use a license key generated from their own Telerik account. In CI/CD pipelines, any of the team's valid license keys can be used, but each developer must use their own key during development.
If you want to cell your application to customers, when you compile the application, and the license is valid at the time of compilation, it stays that way, forever. You can sell your library for years, the application will stay the same as it was at the moment it was compiled.
Please let me know if you have other questions.
Rank 2
Bronze
Iron
Iron
the second part is not my case, I don't want to sell libraries, I was just thinking about consequences of requiring Telerik license also in the main program, which just references libraries using Telerik and which itself doesn't use Telerik. Because in the current state, when license is required in main "exe" assembly, which only references libraries with Telerik, it requires Telerik license also on client side, whether it's another developer or a customer. And also I have to handle Telerik licensing in all my applications which only references that library.
Hello, Marian,
The licensing check is only at a build-time. Every time you compile the project, the version of UI for WinForms looks at the license key and checks to see if it's version is in the list of licenses. There's no runtime check to looks up your account to see what you have up there.
If your attempt is to provide your project to another developer, then yes, he/she will need a license key to develop. Every developer must use a license key that is associated with their personal Telerik account.
I would recommend you to check our Purchasing and Licensing FAQs that covers different cases.
However, if you still have some doubts or questions, feel free to submit a support ticket from your Telerik account and we will continue the discussion there. Thank you for your understanding.
Let me know if you have additional questions and I would be glad to help.
Rank 2
Bronze
Iron
Iron
Hello, no, as I wrote, I was just thinking about consequences. Yes, I know it's only at build time. And no, I don't want to provide project to another developer. I was thinking about scenario, that I develop a library (dll) with some controls using Telerik. Some other developer want to use my library, but he doesn't use Telerik in his project, he doesn't even have Telerik installed, he just references my library dll and use some my control. So is it true, that according to Telerik licensing, he also needs to have official Telerik license, even if he doesn't use Telerik directly?
You wrote this in some previous post: "We do officially support such cases. You described two different cases - using the same library from another developer, AND selling the library to customers. The license key that activates is user-specific.". So how do you support such cases, each "client" have to have Telerik license? For me, it's only little bit annoying that I have to add Telerik Licensing NuGet package to all my programs using that library, and I don't understand, why is the licensing applied to main program and not to the specific assembly that uses Telerik controls.
And in some other previous post, you wrote this: "If you want to sell your application to customers, when you compile the application, and the license is valid at the time of compilation, it stays that way, forever. You can sell your library for years, the application will stay the same as it was at the moment it was compiled.". But from my tests, it's not so true, yes, license is "attached" as assembly attribute in the time of compilation (by NuGet package or manually by scripting license), but it seems that in the runtime, Telerik controls check if the license is valid in the startup exe assembly, not in the specific assembly where that control is located.
Hello, Marian,
Every developer who is using a Telerik component in any form must use a license key that is associated with their personal Telerik account.
We understand that installing the Telerik Licensing NuGet to all programs is a little annoying for you, but it is required to trigger the licensing validation. At this moment, the licensing is not relying on transitive dependencies. This is why Telerik.Licensing NuGet package is required as a reference to the main project as well, not only to libraries. Yes, Telerik controls check if the license is valid is performed in the startup exe assembly as well. I will pass your feedback to the licensing team, so that we can further discuss it and think of any possibilities to improve the licensing mechanism for our clients.
Thank you for sharing your thoughts with us.
Rank 2
Bronze
Iron
Iron
Hello, Marian,
Sharing your opinion is appreciated. For now, obtaining a dev seat for work with Telerik UI for WinForms is required to allow you to develop code using our components. We have our reasons to validate the license, like we do at the moment. However, we are constantly working on improving the Telerik product detection and handling different client scenarios such as yours when using our components inside libraries. We will have your opinion in mind. Thank you!
Regards,
Nadya
Hi!
Have I to install this nuget package for every project in my solution?
Thank you for answer!!!
Hello, Vitalii,
Yes, I confirm that you need to install Telerik.Licensing NuGet for every project where Telerik UI for WinForms controls are used.
If you have other questions, do not hesitate to contact me.
Hello, Vitalii,
The set up of Telerik Reporting License Key is similar to that for WinForms components. The exact steps on how to activate Telerik Reporting are described here: Activating Telerik Reporting.
Note that the license key is one and contains all the necessary licensing information for all the Telerik products you have purchased. Can you please make sure that you downloaded your latest licensing key from your account and you did not modify it in any way. Also, can you confirm is your telerik-license.txt file added to %AppData%\Telerik\ directory?
Then, add the Telerik.Licensing package from the store as a project dependency. After you make sure that these steps are completed, you can clean, then rebuild your projects to ensure that Visual Studio keeps the new changes.
Please let me know if you need further assistance in activating Telerik Reporting?
I have added this file to C:\Users\MyProfile\AppData\Roaming\Telerik and for every project too.
I have added nuget package for every project.
I have even reloaded my notebook twice :)
Result is the same.
Probably something wrong with catalog C:\Users\MyProfile\AppData\Roaming\Telerik? But this path takes me exactly there with File Explorer and %AppData%\Telerik\
Hi,
In the long run I have created TelerikLicensing.cs for every project where I use Telerik Reporting and put my licenses in it.
This helped and project works fine.
Hello, Vitalii,
I am glad to hear that you managed to set up the TelerikLicensing.cs with the license key for every project where you use Telerik Reporting, and now the project works fine.
If you have any other questions, do not hesitate to contact me.