Frequently Asked Questions about Your Telerik UI for .NET WinForms License
This article lists the answers to the most frequently asked questions (FAQs) about working with the Telerik UI for .NET WinForms license key.
Does the license key expire?
Yes, the license key expires at the end of your subscription:
- For trial users, this is at the end of your 30-day trial period.
- For commercial license holders, this is when your subscription term expires.
You need to download and install a new license key after:
- Starting a new trial.
- Buying a new license.
- Renewing an existing license.
- Upgrading an existing license.
An expired perpetual license key is valid for all Telerik UI for .NET WinForms versions published before the license's expiration date.
Will Telerik UI for .NET WinForms function with an expired license key?
This depends on the Telerik UI for .NET WinForms license type (perpetual, subscription, or trial):
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Perpetual licenses will continue to function normally with an expired license key. However, the following will happen if you update or install a package version which is released after the expiration date of the license:
- A watermark appears on application startup.
- A modal dialog appears on application startup.
- A warning message is logged in the build log.
See the Invalid License section for more information.
Subscription licenses will prevent you from building the application with an expired license key. Deployed applications will continue to function normally.
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Trial licenses will prevent the applications from functioning normally once the trial period has expired. The following will happen if you try to build or run the application:
- A watermark appears on application startup.
- A modal dialog appears on application startup.
- A warning message is logged in the build log.
See the Invalid License section for more information.
I updated the Telerik UI for .NET WinForms version in my project and license errors appeared. Why?
The most likely cause is that the new Telerik UI for .NET WinForms version was released after the expiration date of your current license or license key. To fix this issue:
- Renew your Telerik UI for .NET WinForms license if necessary.
- Download a new license key file and use it to activate the components.
Can I use the same license key in multiple builds?
You can use your personal license key in multiple pipelines, builds, and environments. However, each individual developer must use a unique personal license key.
Do I need an Internet connection to activate the license?
No, the license activation and validation are performed entirely offline.
Do I have to add the license key to source control?
No, you do not have to add the telerik-license.txt license key file or its contents to source control.
Build servers must use the TELERIK_LICENSE environment variable described in Adding the License Key to CI Services.
Do not store the license key in plain text, for example, in a GitHub Actions Workflow definition.
What happens if both the environment variable and the license key file are present?
If both the TELERIK_LICENSE environment variable and the telerik-license.txt file are present, then the environment variable will be used.
To use the license key file, unset the environment variable.
What happens if several license key files exist?
If both a global and a project-specific telerik-license.txt files exist, then the project-specific license key will be used.
My team has more than one license holders. Which key do we have to use?
- Every developer must be assigned their own license or seat.
- Every developer must use a license key that is associated with their personal Telerik account.
- In a CI/CD environment, use any of the license keys in your team.
Are earlier versions of Telerik UI for .NET WinForms affected?
No, versions released prior to January 2025 do not require a license key.