Unable to start Blazor Web App debug #63064
Description
This issue has been moved from a ticket on Developer Community.
[severity:It's more difficult to complete my work]
After some Balzor Web App restarts during debug, VS it isn't able start project anymore with a build error:
Severity Code Description Project File Line Suppression State
Error (active) MSB4018 The "ApplyCompressionNegotiation" task failed unexpectedly.
System.ArgumentException: An item with the same key has already been added.
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at Microsoft.AspNetCore.StaticWebAssets.Tasks.ApplyCompressionNegotiation.Execute()
at Microsoft.Build.BackEnd.TaskExecutionHost.Execute()
at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() CertificatesCreator C:\Program Files\dotnet\sdk\9.0.300\Sdks\Microsoft.NET.Sdk.StaticWebAssets\targets\Microsoft.NET.Sdk.StaticWebAssets.Compression.targets 247
The only way to restore it is to close VS, delete .vs folder and restart.
Original Comments
Feedback Bot on 5/28/2025, 09:44 AM:
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