The default XML namespace of the project must be the MSBuild XML namespace error after Installing .Net Core 3 in Visual Studio 2017.0

1
votes

I had 3 projects in a C# solution in Visual Studio 2017, All 3 projects were loaded correctly, but I was getting dependency errors on missing 

.NETFramework 4.0
.NETFramework 4.6.1
.NETStandard 1.3
.NETStandard 2.0

Looking online, I saw that I needed .Net Core SDK So I download the latest SDK for .NET Core 3

Now 2 of the 3 projects would not load with the error

The default XML namespace of the project must be the MSBuild XML namespace

Searches on this error all point to needing Visual Studio 2017 for new project file format

But I am already using Visual Studio 2017. So what is causing these projects to not open, did they change it again? How do I fix this?

Thanks

1
c#windowsvisual-studio-2017

1 Answers

2
votes

  1. You need Visual Studio 2019 if you want to use .NET Core 3.

  2. If you want to stay with Visual Studio 2017 for some reasons - you can use .NET Core 2.1 which is supported in Visual Studio 2017.

    .NET Core 2.1. has LTS (Long Term Support) which ends in 2021.