VS Code IntelliSense not working for Unity3d
Had the same problem using VSCode 1.41.1 and Unity 2019.4.0f1.
I was able to fix it by following these steps:
- download & install the .Net Framework 4.7.1 Developer Pack here:
https://dotnet.microsoft.com/download/dotnet-framework/thank-you/net471-developer-pack-offline-installer
in Unity, go to Edit > Project Settings > Player > API Compatibility Level and change it to .NET 4.x
restart VSCode & Unity
IntelliSense works fine now and I don't get any errors when loading .cs files in VSCode anymore.
In the latest version of VS Code and Omnisharp, I had the same problem and solved enabling this option in Unity:
Edit > Preferences > External Tools > Generate all .csproj files.