Hi @Dutta, Pijush ,
As far as I think,there are two ways you could try:
1.Open ‘Package Manager Console’ and select the project present where WebAPI is present and run the following code:
Install-Package Microsoft.AspNet.WebApi -IncludePrerelease
2.From ‘Manage NuGet Packages’ from Tools > NuGet Package Manager uninstall WebAPI libraries and reinstall WebAPI new libraries, where in you may find back missing libraries.
Best regards,
Yijing Sun
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