Lately I couldn't install Xamarin for Visual Studio because my username was written with Russian symbols. I renamed this folder, then changed every single key with my old username in regedit, but it didn't help.
Then I decided to reinstall every app associated with Xamarin and Visual Studio (including the Java JDK, and Android SDK and NDK). In the SDK manager I tried to install every package, but my Android folder grew to more than 40GB in size, so I stopped the install process.
I can't understand why my AVD Manager looks like this.
Use Xamarin Android Player Download
It is much faster and more productive than a standard emulator