VirtualBox won't open. Error code 0x80040154


VirtualBox won't open. Here's what the error says:

Failed to create the VirtualBoxClient COM object.
The application will now terminate.

Callee RC: REGDB_E_CLASSNOTREG (0x80040154)


It all started when I tried to install "Xamarin Android Player" and it installed a separate version of VirtualBox (I was originally on version 5.0.12, it tried installing version 5.0.4), so I tried opening it and it failed. I tried opening VirtualBox and I got that error, and it kept giving me that error through every version I installed (2.2 to 5.0.15) and I'm completely stumped.

My specs:

  • Computer model: Asus TransformerBook T100
  • CPU: 1.88 GHz quad-core Intel Atom CPU
  • RAM: 2 GB of RAM (I don't know what type)
  • Storage: 32 GB SSD with 3 GB remaining before install (424 MB after)
  • Operating system: Windows 8.1 with Bing

What can I do?

asked on Super User Mar 18, 2016 by MrThrall • edited Mar 19, 2016 by Scott

3 Answers


You will have to uninstall that Xamarin player AND Virtualbox completely. Then remove all traces of both that may have been left behind (Revo Uninstaller is a good tool for that).
If you have a system-restore point dating from before you attempted to install Xamarin it may be less hassle to go back to that.
Reboot and then FIRST install Xamarin, then VirtualBox.
Oldest version FIRST.

It is possible that that combination doesn't work either. If that is the case you will have to again completely uninstall both and then decide which one you really need and only install that.

Please note: Because you have been trying multiple versions of VirtualBox without cleanly uninstalling any of them it is possible your Windows installation is already damaged to the point it is no longer possible to get back into a clean state. If that is the case you hopefully have a restore point dating from before the time problems started. If not a re-install will be needed...

answered on Super User Mar 18, 2016 by Tonny

I actually fixed it... all i had to do was delete the ".virtualbox" folder in "C:/Users/"User"/.Virtualbox:(replace "User with your account's name"

thanks for the help guys. I really appreciate you guys giving me advice.

answered on Super User Apr 3, 2016 by MrThrall

I havve solved the error:

Failed to create the VirtualBoxClient COM object. The application will now terminate.

Callee RC: REGDB_E_CLASSNOTREG (0x80040154)

  1. G to your USER folder ie Document&settings or Your Username folder

  2. You will see the .virtualbox folder

  3. Click on that folder and remove the virtualbox.xml file and the virtualbox.xml-prev file

  4. Again run vbox, it will automatically create the above file and it will run perfectly.

answered on Super User Sep 10, 2016 by sarvesh • edited Sep 10, 2016 by DavidPostill

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