How do I fix “Failed to sync vcpu reg” error?

I’m trying to use the Intel HAX x86 emulator for Windows (8, if that matters). I installed everything and created an AVD for the android version, and everything appears correct, but when I run it, I get this output:

Starting emulator for AVD 'x86_QVGA_Level10'
emulator: device fd:1044
HAX is working and emulator runs in fast virt mode
emulator: Failed to sync vcpu reg
emulator: Failed to sync HAX vcpu context

and the emulator won’t run. The significant part of this error (Failed to sync vcpu reg) is not mentioned ANYWHERE online, except in the source code for the HAX itself, but I can’t figure out how to make any sense of this.

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  • 30 Solutions collect form web for “How do I fix “Failed to sync vcpu reg” error?”

    Make sure you don’t have any virtual machines running. In my case, I had genymotion running which was causing this error.

    I had virtualbox running. Killing the VM allowed allowed the emulator to run.

    If you are running Docker you would have to take the virtual machine down

    docker-machine stop default

    This assumes your docker machine is called default. If you want to check the name use
    docker-machine ls

    A simpler solution; open virtuabox and stop the vm 🙂

    I had this problem. For me it was the HAXM version.

    When you get a new version of HAMX through the SDK Manager, it tells you that it is installed. It is not. You must go to this folder:

    <Android SDK>\extras\intel\Hardware_Accelerated_Execution_Manager\

    and run intelhaxm-android.exe manually. In my case, I had 1.0.6 and upgraded to 1.1.

    I think that what caused the error in the first place was that some other part of the SDK that I had updated needed 1.1.

    As mentioned by other answers, make sure no VirtualBox and docker service is running with following command in mac. (systemctl in Linux)

    $ launchctl list | grep 'VirtualBox\|docker'
    -       0   com.docker.helper
    640     0   com.docker.docker.2032
    31736   0

    If so, kill the VBox and docker service.

    launchctl stop
    launchctl stop com.docker.docker.2032
    1. Stop GENYMOTION (open VirtualBox instance if any instance is running, stop it).
    2. Open AndroidStudio -> Run AVD Manager-> run AndroidStudio virtual device.

    Latest Android Emulators are not able to run in parallel with GENYMOTION

    “vcpu reg” are “Virtual CPU REGisters” that exist on many processors that have things like multiple cores, hyperthreading, or other features that enable higher layers to believe that there is more than one CPU present when there isn’t — such as today’s x86s. No reason to go in to detail — you can imagine that getting a coherent, single “virtual CPU context” is necessary for the kind of hardware virtualization that HAX offers.

    Normally, it’s not a problem to run multiple virtual machines of various sorts simultaneously. But if one of them crashes, or misbehaves, or just decides to be a hog, HAX might find that it just can’t put together a coherent virtual machine, because it can’t sync a virtual CPU context for itself. It’d be like trying to run a real machine with no CPU.

    Bottom line is open task manager and kill things that you don’t need and that look like they might be holding virtual machine resources. In the worst case, a reboot is almost certain to fix the problem.

    Quick steps:

    1. Stop all VirtualBox Virtual Machines (i.e. vagrant halt), quit VirtualBox.
    2. All docker-machines should be stopped, too. Quit Docker.

    I was getting the same error. I’m guessing there are various reasons for this error, but in my case it was because of a service named “.NCG”. The service is Network Content Guard by Inka Entworks, and seems to be some type of DRM solution. Once uninstalled, the emulator worked fine using HAX.

    In my case, it turned out this problem was caused by having a webcam selected as “Front Camera” in the settings for the AVD. Setting it to “Emulated” fixed this problem for me.

    I faced this issue because I had my virtual box running with Ubuntu on it. When I shut down my virtual box I did not face this issue.

    I got the same error on my windows 8 install.

    Things you could try:

    • lower the amount of memory for the emulated device (and/or close other applications)
    • disable GPU emulation
    • remove the pass-through webcam

    For me, the error occurs when I try to attach a physical webcam to the emulated android instance.

    This kept failing until I changed it to [x] Use Host GPU as shown in pic.

    AVD Set up

    This happened to me also when I was trying to run both VirtualBox and Android emulator in a MacOS machine. As others have mentioned above currently it is not possible to run both (i.e. VirtualBox and X86 -Intel based emulator) in MacOS and not sure about the other platforms.
    If we need to run both we can choose ARM based emulator. (arm based emulators are normally slow)

    I’m running boot2docker vm, just down it solved the issue.

    boot2docker down

    Make sure you don’t have any virtual machines running. In my case, I had genymotion running which was causing this error. when i kill genymotion’s Process and kill all Oracle VM VirtualBox related process then it work
    by wangshiming
    don’t thankyou me

    Ya, i had virtual box running and was getting this error, shutting it down fixed the error.

    I was on a mac and had this problem. I did not think I was running a VM (I have vbox but it isn’t running). I restarted my computer and before starting any other apps I tried the emulator and it works fine.

    If your CPU supports throttling (like Intel’s SpeedStep) try to disable that feature in your BIOS. It’s kind of a quickfix but at least it worked.

    I think it must be a variety of reasons cause this failure. In my case, since I installed the Google input method software, “Failed to sync vcpu reg” appeared. This was the one and only change before normal working. So, after uninstall the Google Input software, it was recovered.just a little reference, although I can’t believe this solution for long time either.

    I had the Windows Virtual PC running (on Windows of course). Once I turned off, the emulator went fine.

    Hope this helps.

    I was trying to launch a Gingerbread 2.3.3 x86 emulator and it would not launch. Changing from x86 to arm made the problem go away.

    For me, the only thing that worked using adv on MacOs Yosemite, is setting the processor to ARM (native CPU of the device – standard 4″ Nexus).

    This is the VirtualBox ticket –

    If you are having any virtual machines running, suspend them and try again.

    For me the answer was to set Enable keyboard input to true under the advanced settings of the virtual device.

    This was the first option I changed on the device, so it is possible that the act of changed an option fixes the error as well based on the wide array of answers above.

    Note: I’ve confirmed previously that no VM’s are running.

    Fixed the problem by changing current version of Java within Windows from Java 8 x64 to Java 7 x86.

    Yes, VirtualBox VMs have to be stopped. I also had to stop Docker for Mac. The error message only mentions VirtualBox, which confused me a little until I realized Docker for Mac is running xhyve.

    Finally, I found the anwer for this question.
    I had exactly the same problem and it was completely solved.

    Virtual device or webcam is rarely the cause of your problem.

    Just install mainboard chipset driver.

    I recommend you to use 3DP chipset autoinstaller.

    Good luck!

    For me it was google appengine running locally.

    Android Babe is a Google Android Fan, All about Android Phones, Android Wear, Android Dev and Android Games Apps and so on.