The type initializer for ‘Sitecore.Install.Serialization.IOUtils’ threw an exception.

Today I’ve been having this problem out of the blue: “The type initializer for ‘Sitecore.Install.Serialization.IOUtils’ threw an exception.” Searching for this error in relation to Sitecore usually points to Newtonsoft.Json.dll as the culprit, but in my case it was Mvp.Xml.dll, that some NuGet or somesuch upgraded to a higher version thus

Random error after upgrading some NuGet packages: “You must add a reference to assembly ‘netstandard, Version=”

Just a very quick write-up on this as it kept me busy for a couple of hours looking for a solution. After upgrading a number of NuGet packages (Microsoft ASPNet WebApi 2.2 Core Libraries, Microsoft ASPNet MVC, HtmlAgilityPack), my perfectly working Sitecore local development setup stopped working, instead throwing the