After upgrading Telerik.ReportViewer.BlazorNative to version 20.2.26.1007, rebuilding a project targeting .NET 9 or later fails with the following error:

Severity Code Description Project File Line Suppression State
Error (active) The asset 'C:\...\BlazorApp1\Debug\net10.0\compressed\14jp1i84hx-{0}-2x8nbomfaf-2x8nbomfaf.gz' can not be found at any of the searched locations 'C:\Users\<user>\.nuget\packages\telerik.reportviewer.blazornative\20.2.26.1007\staticwebassets\css\reporting-blazor-viewer.css.map' and 'C:\Users\<user>\.nuget\packages\telerik.reportviewer.blazornative\20.2.26.1007\staticwebassets\css\reporting-blazor-viewer.css.map'. BlazorApp1 C:\Program Files\dotnet\sdk\10.0.301\Sdks\Microsoft.NET.Sdk.StaticWebAssets\targets\Microsoft.NET.Sdk.StaticWebAssets.Compression.targets 276

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The issue occurs because the NuGet package declares a CSS source map as a static web asset but does not include the corresponding file.

For the available workarounds, refer to the following Knowledge Base article: Missing CSS source map causes build failure in .NET 9 and later with Telerik.ReportViewer.BlazorNative 20.2.26.1007