I wanted to run Linux through my Winows 8.1 machine using VirtualBox as hypervisor. After I tried adding Ubuntu (or Fedora, on another instance) to the list of virtual machines, I clicked Start, but it refused to run and an error popped up, saying:

Result Code: E_FAIL (0x80004005)
Component: Machine
Interface: IMachine {480cf695-2d8d-4256-9c7c-cce4184fa048}

and another error message was also given, saying:

Error relaunching VirtualBox VM process: 5
Command line: '81954AF5-4D2F-31EB-A142-B7AF187A1C41-suplib-2ndchild--comment Fedora32 --startvm fd699e30-a77b-4eac-8ced-1210d756855d --no-startvm-errormsgbox' (rc=-104)

  • right click on the vm machine that has problem and click "Discard saved state", this worked for me Jan 3, 2021 at 7:48

3 Answers 3


Possible solution: The following registry key seems to cause trouble:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers] "C:\Program Files\Oracle\VirtualBox\VirtualBox.exe"="DISABLEUSERCALLBACKEXCEPTION"

See if this entry exists. If so, delete it and try again.

You may also need to disable your antivirus. If nothing works, try one of the following:

  • Uninstall your antivirus (NOT RECOMMENDED)
  • Replace your antivirus with Microsoft Security Essentials Pre-release (4.6)
  • Give up on VBox and use Hyper-V

Also, as a side note, if you are using Windows 8.1 Pro or higher, try Microsoft's Client Hyper-V. I extremely prefer it over VBox.

  • I am running Windows 7 and that particular Registry Key does not exist. I have gone back to version 4.3.12 and it is working fine.
    – user348166
    Jul 20, 2014 at 13:41
  • 1
    It was the antivirus (avg) that was causing the problem for me. Thank you!
    – brettville
    Jul 24, 2014 at 3:25
  • 1
    You're welcome. Realize I do NOT recommend uninstalling/disabling your antivirus, rather downgrading VBox or using Hyper-V instead. Jul 24, 2014 at 3:36
  • Wonder, how much is the cost of Hyper-V. This is the second time I had to go through this hassle..
    – alpha_989
    Feb 16, 2018 at 4:01

Although downgrading to VirtualBox 4.3.12 works, so does upgrading to 4.3.16.

I had the exact same problem as user135626 today, probably as a result of a Windows update and a Security configuration change.

When looking for newer versions from INSIDE VirtualBox 4.3.14, I was told that I was running the latest version. Which was incorrect.

Version 4.3.16 is available for download from https://www.virtualbox.org/wiki/Downloads

  • Version 4.3.18 works as well, the problem occurred after installing AVG free, upgrading Virtualbox fixed it.
    – Sven
    Oct 25, 2014 at 12:47

Look at this https://www.virtualbox.org/ticket/13187Virtualbox 4.3.14 crashes

The solution so far (2014-8-17) seems to be downgrade to 4.3.12 or use 4.3.15 testcase .


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