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Re: Error "Failed to open a session for the virtual machine..."

Posted: 1. Oct 2016, 10:30
by mpack
I see you have two antivirus packages installed, Malwarebytes and AVG. I'm suspicious of the latter, but you can try disabling both - see if the problem goes away. IMHO two different AV packages is often a bad idea.

Another thing to try is disabling 3D acceleration, see if the problem goes away. If it does then it's probably an unsigned graphics driver, you should look for updates.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 4. Oct 2016, 06:25
by motecl
mpack wrote:I see you have two antivirus packages installed, Malwarebytes and AVG. I'm suspicious of the latter, but you can try disabling both - see if the problem goes away. IMHO two different AV packages is often a bad idea.

Another thing to try is disabling 3D acceleration, see if the problem goes away. If it does then it's probably an unsigned graphics driver, you should look for updates.
thanks for the quick reply
I unistall both AV and the 3D but I still have the problem :C
here it the new log
thanks Appreciate your help guys

Re: Error "Failed to open a session for the virtual machine..."

Posted: 4. Oct 2016, 10:03
by mpack
Well, the only remaining error I see is "unknown status" loading user32.dll, a critical Windows system DLL. Perhaps you should try running "sfc /scannow" from an admin command line.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 3. Nov 2016, 08:09
by pxpc2
I'm also getting the error. I tried removing AVG, but that didn't solve it; been looking for solutions for a few hours now and nothing, also tried installing different versions/running as admin and etc; any help is appreciated! :D
My log file is attached.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 3. Nov 2016, 14:01
by scottgus1
pxpc2, it's usually a good idea to start your own new thread, just in case your issue isn't related to the OP or the other folks who have glommed on.

That said, your hardening log also shows an issue over user32.dll. Did you try Mpack's suggestion in the post above yours?
mpack wrote:try running "sfc /scannow" from an admin command line.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 3. Nov 2016, 18:59
by pxpc2
I'm sorry, indeed should've created a new thread. Anyways, I hadn't realized the issue was also with user32.dll, my bad. Mpack's suggestion worked! Thank you all a lot.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 4. Nov 2016, 10:59
by mpack
"Failed" is a symptom, not the disease. It can have many causes, and the above discussion hasn't covered them all. Nor could it, without the topic turning into a sprawling mess. So yes it is best to start your own topic and give your exact symptoms and a log file.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 5. Jan 2017, 00:33
by CaptGreyBeard
I created an account just to say:
Windows defender Real Time scanning was causing my issue. Turned it off. Boom, everything works like magic again.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 5. Jan 2017, 00:56
by socratis
@CaptGreyBeard
That's got to be the first that I remember seeing Windows Defender causing a problem. Interesting...
Can you give specific information about version numbers for the OS and Defender, including if you can even update dates.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 5. Jan 2017, 05:57
by BillG
A bit of a surprise to me too. I have had Defender real-time scanning on ever since Windows 10 came out and have never had a problem with VirtualBox (or any other program) caused by it.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 8. Feb 2017, 18:48
by ZiggyLink
I understand this is an old thread, but in my case the Citrix Streaming Profiler was causing the message referenced by the OP. Uninstalling it resolved the issue for me. Hope this helps someone out there!

Re: Error "Failed to open a session for the virtual machine..."

Posted: 9. Feb 2017, 23:50
by Renzo73
same error here. Ubuntu 16 host.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 10. Feb 2017, 00:09
by socratis
@Renzo73
Please pay more attention next time. This is the Windows Hosts section. You may have a similar error, but no way it's the same thing. Please open a new thread.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 4. Mar 2017, 18:14
by pchaitat
I have got a similar error too.

My environment:

- Windows 7 (64-bit) Host OS
- Windows 7 (64-bit) Guest OS
- VirtualBox, the latest stable version for Windows Host as of Mar 4, 2017 which is version 5.x (Sorry, I can't remember the exact version as the host is on a remote location and I don't have access to it anymore)

My language: Tinglish

When I tried to start my Guest OS, VirtualBox showed an error dialog box. An error log was created in a file which had "*hardening*" as part of the filename.

After spending some time looking for a solution on the Internet, I tried a different way of starting my Guest OS. I tried, "Detachable Start" and the Guest OS booted up!

Hope that helps.

Re: Error "Failed to open a session for the virtual machine..."

Posted: 4. Mar 2017, 18:27
by socratis
pchaitat wrote:I tried, "Detachable Start" and the Guest OS booted up!
That's definitely not a solution, that's a workaround at best. What you have is something that's preventing the guest window from being created on the host by normal means (because it eventually gets created). To me that sounds like an installed hacked theme or some system DLL having being replaced. Both of those could have been seen in that "*hardening*" ... thing.