The android emulator was hanging on startup of older emulator images and after a lot of trying and reading the solution was quite simple: 1. quit Android Studio, 2. delete the directory ".android" (actually I renamed it to ".android_bak") and 3. when restarting Android Studio the directory was recreated and all emulator images were running fine. And the reason was that long ago I did some configuration changes in ".android" which were not compatible anymore with the new Android SDK.