Android emulator not showing in Visual Studio

I had a similar issue using VS 2015 with Android Emulator Manager (AVD). I have to start my emulator from the Android Emulator Manager and then it will show up in the debug devices drop down list, but one day it didn't show up. Tools > Android > Restart Adb Server fixed it for me.

For me on VS 2017 it was a matter of my user not being an admin. The issue is that unless the ANDROID_SDK_HOME environment variable is set it will create a .android folder in the %userprofile% directory and visual studio uses that to look for emulated devices. But when AVD is run as an administrator it uses whatever admin profile you use for admin priveledges and uses the .android folder under that user for managing emulated devices.

Following the link shows a guide on how to set the environmental variable so that all users look in the same location for emulated devices.

https://www.mysysadmintips.com/windows/clients/761-move-android-studio-avd-folder-to-a-new-location

Similar issue here, I had a series of android emulators setup in Visual Studio 2015 Android Emulator Manager (AVD), but when I tried to run a xamarin.forms sample, none of the emulators I created were showing up in the debug targets drop-down.

What fixed it for me was to set the android project as StartUp Project manually (right-click project > set as startup project)

For some reason (bug/feature?) it doesn't suffice to just change the selected item from Visual Studio menu drop-down 'startup projects'. Hope this helps!