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"Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 15:36
by tot94
Hello,

I have a problem launching VirtualBox..
I don't know why this error message suddenly appears :

Image

I have uninstall et install again, no result..

Have you got any solution ??

Regards,

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 15:52
by mpack
That error message implies that VirtualBox has not been installed.

Describe how you are installing VirtualBox? Obviously if you are doing it wrong then repeating the process will not help.

The right way is to install as the correct user (not the "Admin" user, or the "Administrator" user), but use "Run as administrator" to run the installer.

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 16:51
by tot94
I download :

VirtualBox 5.1.6 for Windows hosts x86/amd64

Then I run it as administrator.

Again the same error message appears...

Start tag expected, '<' not found.
Location: 'C:\Users\T\.VirtualBox\VirtualBox.xml', line 1 (0), column 1.
F:\tinderbox\win-5.1\src\VBox\Main\src-server\VirtualBoxImpl.cpp[549] (long __cdecl VirtualBox::init(void)).


Result Code:
E_FAIL (0x80004005)
Component:
VirtualBoxWrap
Interface:
IVirtualBox {0169423f-46b4-cde9-91af-1e9d5b6cd945}
Callee:
IVirtualBoxClient {d2937a8e-cb8d-4382-90ba-b7da78a74573}

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 16:56
by scottgus1
tot94 wrote:Then I run it as administrator.
As in this?
Then I right-click-choose "run as administrator" in the popup menu

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 16:58
by tot94
Image
Log detail :
Start tag expected, '<' not found.
Location: 'C:\Users\T\.VirtualBox\VirtualBox.xml', line 1 (0), column 1.
F:\tinderbox\win-5.1\src\VBox\Main\src-server\VirtualBoxImpl.cpp[549] (long __cdecl VirtualBox::init(void)).

Result Code: E_FAIL (0x80004005)
Component: VirtualBoxWrap
Interface: IVirtualBox {0169423f-46b4-cde9-91af-1e9d5b6cd945}
Callee: IVirtualBoxClient {d2937a8e-cb8d-4382-90ba-b7da78a74573}

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 17:03
by scottgus1
The little picture posted above does seem to show right-click-run-as-admin being used.

The "Start tag expected, '<' not found" sounds like a possibly malformed master guest registry.
Here's an idea:

reboot your host.
go to c:\Users\{your-user-name}. Inside that folder will be a ".Virtualbox" folder. Move this .Virtualbox folder onto the desktop.

Now try running Virtualbox. If the GUI window comes up and you have no guests showing, the I would diagnose a bad Virtualbox.xml in the .Virtualbox folder

Post back if Virtualbox launches with no guests listed.

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 17:06
by tot94
You are right, now it works !
What I am suppose to do now ? I let the folder on the folder ?

I have no guest list because I have unistall VirtualBox before..

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 17:11
by scottgus1
OK, so I would now reboot the host again to clear out any running Virtualbox processes.

Then go back to c:\Users\{you} and delete the new .Virtualbox folder.

Copy the .Virtualbox folder froom the desktop to the c:\Users\{you} folder. Keep the copy on the desktop as a backup, because we're going to footle about with the files in the c:\Users\{you}\.Virtualbox folder

In the c:\users\{you}\.Virtualbox there is very likely a "VirtualBox.xml" and a "VirtualBox.xml-prev". Rename "VirtualBox.xml" to "VirtualBoxbad.xml-bad" and then rename "VirtualBox.xml-prev" to "VirtualBox.xml".

Fire up Virtualbox again and let us knw what happens.

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 17:15
by scottgus1
I just noticed this part:
tot94 wrote:I have no guest list because I have unistall VirtualBox before..
If you had no guests before, then just deleting the .Virtualbox folder and starting Virtualbox will let you get going.

Keep in mind that any Preferences changes in the main Virtualbox window will need to be re-set.

If you do get a guest set up and the same "Start tag expected, '<' not found" error occurs again one day, you can re-register the guests in the refreshed Virtualbox by finding and double-clicking the guests' .vbox files.

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 17:21
by tot94
You procedure works well
I thought the VirtualBox uninstall would have delete my hosts but instead they appear as inaccessible..
I will delete them again
Thank you :)

Re: "Failed to acquire the VirtualBox COM object."

Posted: 13. Oct 2016, 20:26
by socratis
tot94 wrote:I thought the VirtualBox uninstall would have delete my hosts guests
I corrected the hosts/guests, since host is your physical computer, guests are the virtual ones. But that's not the point. Guests are "documents", "data". Uninstalling LibreOffice or MicrosoftOffice does not delete your documents, right? Same with VirtualBox. Uninstalling VirtualBox does not delete your guests (your VMs).

Re: "Failed to acquire the VirtualBox COM object."

Posted: 16. Dec 2016, 06:31
by elisatih
I have the same problem.

I try this:
I remove C:\Users\<username>\.VirtualBox
and
SOLVED! My VirtualBox apps is run...

Re: "Failed to acquire the VirtualBox COM object."

Posted: 15. Nov 2018, 20:35
by niceguy42
tot94 wrote:Log detail :
Start tag expected, '<' not found.
Location: 'C:\Users\T\.VirtualBox\VirtualBox.xml', line 1 (0), column 1.
F:\tinderbox\win-5.1\src\VBox\Main\src-server\VirtualBoxImpl.cpp[549] (long __cdecl VirtualBox::init(void)).

Result Code: E_FAIL (0x80004005)
Component: VirtualBoxWrap
Interface: IVirtualBox {0169423f-46b4-cde9-91af-1e9d5b6cd945}
Callee: IVirtualBoxClient {d2937a8e-cb8d-4382-90ba-b7da78a74573}
This worked great for me but seems like a band-aid. Is there a better solution or a reason why this happens? I have uninstalled and reinstalled as admin and this kept happening.

Re: "Failed to acquire the VirtualBox COM object."

Posted: 16. Nov 2018, 11:04
by mpack
We can't tell you why files on your host are being corrupted. It's not something that we see generally.

Re: "Failed to acquire the VirtualBox COM object."

Posted: 27. Sep 2020, 08:20
by Katarina Player
I got this problem too, my solution was that I got into task manager and ended all processes that were related to Virtualbox, after that I just started it again and it worked