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Activation Errors and Warnings

Updated on Oct 19, 2026

Starting with the 2025 Q1 release, Telerik Document Processing reports licensing problems through build messages and runtime indicators. This article explains invalid licenses, distinguishes build-time messages from runtime behavior, and describes the related warning and error codes.

The result depends on the license type and whether you build or run the application:

During a build, Telerik.Licensing reports a warning or error when it cannot validate the license.
At runtime, a missing or invalid trial license can prevent normal operation and display a watermark and modal dialog box.
An expired perpetual license can continue to work in a deployed application. Rebuilding with a product version outside the license validity period produces licensing indicators.
An expired subscription license can continue to work in a deployed application. Rebuilding the application produces licensing indicators.

Click the OK button in the modal dialog box to close it and remove the banner until the next application startup.

Invalid License

An invalid license can be caused by any of the following:

Using an expired subscription license—subscription licenses expire at the end of the subscription term.
Using a perpetual license for product versions released outside the validity period of your license.
Using an expired trial license.
A missing license for the product.
Not installing a license key in your application.
Not updating the license key after renewing your product license.

License Warnings and Errors

When you use the product in a project with an expired or missing license, the Telerik.Licensing build task reports the following conditions:

Condition or message	Code	Resolution
`No Telerik or Kendo UI product references detected in project.`	TKL001	If you use Telerik products and see this message, update the Telerik.Licensing package to version 1.4.9 or later. If you do not use Telerik products, remove the Telerik.Licensing NuGet reference from your project.
`No Telerik and Kendo UI License file found.`	TKL002	Install a license key to activate the UI components and remove the error message.
`Corrupted Telerik and Kendo UI License Key content in: [file path or environment variable name].`	TKL003	If you use a `telerik-license.txt` file to activate the components, download a new license key file and place it in your home directory. Make sure to use a license key and not a script key. If you use the `TELERIK_LICENSE` environment variable to store your license key, download a new license key, update the content of the environment variable, and make sure it contains the entire key.
`Unable to locate licenses for all products.`	TKL004	Your license is not valid for all Telerik and Kendo products added to your project. If you have already purchased the required license, then update your license key.
`"Telerik Document Processing Libraries" product is not listed in your current license file.`	TKL101	Review the purchase options for the listed products. Alternatively, remove the references to the listed packages from the project file (`.csproj`).
`Your current license has expired.`	TKL102	Use a license that covers the product version. Download a new license key after renewing, or downgrade as indicated in the message.
`Your subscription license has expired.`	TKL103; TKL104	Renew your subscription and download a new license key.
`Your trial license has expired.`	TKL105	Purchase a commercial license to continue using the product.
`Services associated with Telerik Document Processing Libraries require a subscription or trial license. Obtain a subscription license.`	TKL403	In Q1 2026, this warning can occur when `Telerik.UI.for.Wpf.AllControls` or `UI.for.WinForms.AllControls` adds Telerik Document Processing Agent Tools. Replace the combined package with individual packages if you do not use the tools. Otherwise, purchase a subscription license. See Resolving the TKL403 Licensing Warning.

Activation Errors and Warnings

Invalid License

License Warnings and Errors

See Also