


I got round this by removing the Microsoft.EntityFramework Nuget library (I had to also remove too, since this depended on it), then adding them both back in, making sure to include at least version 6.2 of the former (otherwise I got another runtime error to do with the FirstOrDefaultAsync method called somewhere!). When I recompiled my solution, it gave a few CS0433 compilation errors with duplicate namespaces for the MinLength and MaxLength directives in some identity user name and password validation code. vs folder (again), which seemed to solve the problem. However, one thing to watch out for - after doing this, Visual Studio recognised my classes but no longer recognised built-in ones (all the referenced namespaces at the top of my controllers were underlined in red). I deleted the packages folder at the base level of my project (somewhat nervously, as I wasn't sure if it was needed), and thought it had solved the problem, but no such luck. I thought I've finally solved the problem by following the advice from Homer.

This cost me a lot of lost time! I've been worked with Visual Studio for about 10 years, and this problem happens occasionally in every version. After working for a few months, Intellisense suddenly stopped.
