FileLoadException with Telerik.Licensing.Runtime After Upgrading to 2026.3.812
Environment
| Product | UI for ASP.NET AJAX |
| Version | 2026.3.812 |
Description
I encounter the following error after upgrading to UI for ASP.NET AJAX 2026.3.812 and Licensing 1.9.1:
Could not load file or assembly 'Telerik.Licensing.Runtime, Version=1.8.2.0, Culture=neutral, PublicKeyToken=98bb5b04e55c09ef' or one of its dependencies.
This issue occurs even though no binding redirects are present in the web.config file.
Cause
The error arises from leftover references to older Telerik assemblies, such as Telerik.Web.Spreadsheet.dll or other outdated Document Processing Library assemblies, still present in the bin folder or project references. These old assemblies reference Telerik.Licensing.Runtime, Version=1.8.2.0, which conflicts with the updated Licensing 1.9.1 runtime.
Starting with version 2026 Q3 (2026.3.812), the RadSpreadsheet component uses a new dependency, Telerik.Spreadsheet.Web, which is distributed as a standalone NuGet package. The old Telerik.Web.Spreadsheet.dll is no longer valid in this version.
Solution
-
Check the
binfolder and deployment packages for leftover assemblies, such asTelerik.Web.Spreadsheet.dll, and delete them. -
Update all project references to the following:
Telerik.LicensingTelerik.Web.UI- Replace
Telerik.Web.Spreadsheetwith the new dependency,Telerik.Spreadsheet.Web. Add it via NuGet or from theAdditionalLibraries/Bin462folder in the Telerik installation package if theRadSpreadsheetcomponent is used.
-
Remove any outdated Document Processing Library assemblies such as
Telerik.Windows.Documents.*andTelerik.Windows.Zip*. Replace them with their updated equivalents. -
Review the Release History for Telerik UI for ASP.NET AJAX 2026 Q3 (2026.3.812) for additional breaking changes or updates.