Fix for the Android Emulator (Android Simulator) crashing during launch

On a recent project I was working on, I wasn’t able to start the Android Emulator/Simulator anymore from within Android Studio. Every time I launched it from Android Studio it would start, but then – without any errors or warnings – close all by itself.

When I switched to launching the Android Emulator from the Command Line instead, I finally got to see an error message:

$ cd $(dirname $(which emulator)) && ./emulator -avd Nexus_5X_API_25
emulator: WARNING: encryption is off
Hax is enabled
Hax ram_size 0x60000000
HAX is working and emulator runs in fast virt mode.
Failed to sync vcpu reg
Failed to sync vcpu reg
Failed to sync vcpu reg
Failed to sync vcpu reg
Failed to sync vcpu reg
Failed to sync HAX vcpu contextInternal error: Initial hax sync failed

Aha, a clue! One Google Search Coupon later it turns out the thing preventing the emulator from running was that other thing using vcpu’s, namely docker.

👉 Killing docker will let you run the Android Emulator without any problems.

I haven’t tested other suggested solutions (such as tweaking the settings of the virtual device), but at least this one did it for me.