I'm just trying to run a simple "Hello World" in Visual Studio. I created a cross platform design. I installed Visual Studio 2017, trying to run does not open the emulator, generating the following error:
Error: Could not find android.jar for API Level 25. This means the Android SDK platform for API Level 25 is not installed. Either install it in the Android SDK Manager (Tools > Open Android SDK Manager...), or change your Xamarin.Android project to target an API version that is installed. (C:\Program Files (x86)\Android\android-sdk\platforms\android-25\android.jar missing.)