I don't know why, but EntityFramework Core has completely vanished for me.It's gone from the Microsoft namespace and does not exist anywhere in the NuGet package browser or even the dotnet CLI direct install.
I tried fully uninstalling and reinstalling visual studio and all associated tools. I've tried reloading the project. I've tried directly injecting it into the csproj file:
<ItemGroup><PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.3" /><PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.1.3"><PrivateAssets>all</PrivateAssets><IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets></PackageReference><PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.3" /><PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.3"><PrivateAssets>all</PrivateAssets><IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets></PackageReference><DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0" /></ItemGroup>Even when I directly copy and past the dotnet CLI command found here (https://www.nuget.org/packages/Microsoft.EntityFrameworkCore) it just doesn't exist.
dotnet:
PS C:\Users\nikkolas\Documents\Nikkolas Diehl\Work\TestAPI> dotnet add package Microsoft.EntityFrameworkCore --version 5.0.6 Determining projects to restore... Writing C:\Users\nikkolas\AppData\Local\Temp\tmp9036.tmpinfo : Adding PackageReference for package 'Microsoft.EntityFrameworkCore' into project 'C:\Users\nikkolas\Documents\Nikkolas Diehl\Work\TestAPI\TestAPI.csproj'.info : Restoring packages for C:\Users\nikkolas\Documents\Nikkolas Diehl\Work\TestAPI\TestAPI.csproj...error: NU1101: Unable to find package Microsoft.EntityFrameworkCore. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packageserror: NU1101: Unable to find package Microsoft.EntityFrameworkCore.Design. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packageserror: NU1101: Unable to find package Microsoft.EntityFrameworkCore.SqlServer. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packageserror: NU1101: Unable to find package Microsoft.EntityFrameworkCore.Tools. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packageserror: Package 'Microsoft.EntityFrameworkCore' is incompatible with 'all' frameworks in project 'C:\Users\nikkolas\Documents\Nikkolas Diehl\Work\TestAPI\TestAPI.csproj'.PM:
Install-Package : Failed to retrieve information about 'Microsoft.EntityFrameworkCore.SqlServer' from remote source 'https://www.nuget.org/FindPackagesById()?id='Microsoft.EntityFrameworkCore.SqlServer'&semVerLevel=2.0.0'. Response status code does not indicate success: 404 (Not Found).At line:1 char:1+ Install-Package Microsoft.EntityFrameworkCore -Version 5.0.6+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+ CategoryInfo : NotSpecified: (:) [Install-Package], Exception+ FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PackageManagement.PowerShellCmdlets.InstallPackageCommandTime Elapsed: 00:00:03.0365187