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Could not load type from assembly 'WindowsBase' error in .NET Core project


Product Version N/A
Product Telerik Document Processing
Used with UI for Blazor, UI for Xamarin, UI for WinUI, UI for ASP.NET Core, UI for .NET MAUI


This exception is thrown when the binaries for .NET Framework are used in a project targeting .NET Core.

Error Message

  • System.TypeLoadException: Could not load type 'System.Windows.Size' from assembly 'WindowsBase'
  • System.TypeLoadException: Could not load type of field 'Telerik.Windows.Documents.Spreadsheet.Expressions.DataStructures.CellReferenceRangeExpressionCache:cellReferenceRangeExpressionCache' (1) due to: Could not resolve type with token 010000da from typeref (expected class 'System.Windows.IWeakEventListener' in assembly 'WindowsBase, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35') assembly:WindowsBase, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35 type:System.Windows.IWeakEventListener member:(null)
  • Could not load file or assembly 'WindowsBase, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The located assembly's manifest definition does not match the assembly reference.


Remove all the binaries related to Telerik Document Processing and add them again making sure that the names of the binaries or NuGet packages do not include 'Windows'.

Although the word 'Windows' is removed from the assembly names for .NET Core, the namespaces still contain it.

See Also

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