I have faced within issue in Rider on Ubuntu 16.04 when tried to create and compile toy example:
The imported project "/usr/share/dotnet/sdk/2.1.301/Xamarin/Android/Xamarin.Android.CSharp.targets" was not found. Confirm that the path in the <Import> declaration is correct, and that the file exists on disk. /home/<user_name>/RiderProjects/AndroidApp1/AndroidApp1/AndroidApp1.csproj
I guess it is some how related to Xamarin template, am I right ? How to fix it ?