Have you encountered the in .NET core? Well, so did! Here's how it happened to me and how I fixed it. type or namespace not found CS0246 error Something strange happened today. I developed a Class Library in .NET Framework and I tested it with the related test library. So I've integrated the library into another project. Everything was fine, I used that library without problems. But, all of a sudden: Error CS0246: The type or namespace name 'XX' could not be found (are you missing a using directive or an assembly reference?). I've been using it for the whole week. I've tested it. I've added the reference, and the Intellisense works as well. What?!? C'mon, the class is here! Clean the solution... nothing happens. Close Visual Studio... still nothing. Have a coffee... well, better now. Suddenly, a doubt: what if I've created it in .NET Core instead of .NET Framework? And, obviously... no, it wasn't that. The Real Way to Fix the Namespace Not Found Error in .NET Core But I was close: the Class Library was in but the application was in . .NET Framework 4.7.2 .NET Framework 4.7.1 It was the patch version! So, I just , and everything went well again. downgraded the class library version through Visual Studio How to Downgrade You can find the version in the Properties screen of the project (right-click on the project in the Solution Explorer or ) in the tab, then under the field. Alt+Enter Application Target framework So, the lesson is: , and check for slight details. know your enemy Previously published at https://www.code4it.dev/blog/dotnet-type-or-namespace-not-found

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How to Fix Error CS0246: "Type or namespace not found" in .NET Core

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