Trying to open a VM config which has the same UUID as an existing virtual machine

You can use VBoxManage internalcommands sethduuid <VDI/VMDK file>(Run from the VBox install directory) to change the HD UUID, but this has two shortcomings: it does not update the .vbox file, and it does not change the machine UUID (I did not find any way to do this with VBoxManage), just the HD UUID.

The following worked for me (Win 7, most recent VirtualBox version):

1. run VBoxManage internalcommands sethduuid <VDI/VMDK file> twice (the first time is just to conveniently generate an UUID, you could use any other UUID generation method instead)
2. open the .vbox file in a text editor
3. replace the UUID found in <Machine uuid="{...}" with the UUID you got when you ran sethduuid the first time
4. replace the UUID found in <HardDisk uuid="{...}" and in <Image uuid="{}" (towards the end) with the UUID you got when you ran sethduuid the second time

You can add the virtual machine after that. Not a very clean solution, but does not seem to cause any problem.

I've found a simpler way to do it.

Clone the existing virtual machine. This creates a new version with presumably a new uuid, but in all other respects it is the same machine.

Then copy the one you want to add, to your \user(your name)\Virtual Box VMs\ (or wherever the location is for your virtual machines) and overwrite all the existing files there, to replace the existing machine.

I would back up the existing machine first just in case, before doing that, but it worked just fine here. Used it to go back to an earlier backup of a VM while keeping the existing version as a clone.

I realize this is an old post but I ran upon this error. I resolved it by:

1. Open Virtual Box Manager
2. Right click on the virtual machine in the Virtual Box Manager
3. Click "Remove"
4. A pop-up will appear. Choose "Remove only" which will simply remove all traces of the virtual box from the Virtual Box Manager
5. Close the Virtual Box Manager
6. Using the Linux file manager, browse to the folder containing the virtual machine
7. Delete (or move) everything EXCEPT the .vmdk virtual hard disk file
8. Open Virtual Box Manager
9. Click "Machine"
10. Click "New"

11. Name the new machine (I used the same name as I originally used)

    NOTE: The name of the machine is will become the name of the directory that will contain the virtual machine so choose wisely and also note that if you want the .vmdk file to reside in the new directory that it will take additional steps in Virtual Box Manager

12. Select the proper Type and Version for the virtual machine that was having the issue and click "Next"
13. Select the memory size you want the virtual machine to have allocated and click "Next"
14. Select "Use and existing virtual hard disk file" and select it by browsing to it's location
15. Select "Create"

Simply follow the prompts from there and then start the virtual machine.

Everything runs fine, no re-activation of windows or etc. required.

You can also clone the existing machine then go into settings and change the storage to use the .vmdk that you had copied earlier.

If you are unable to launch due to this error, simply 'Remove...' the entry from the 'Oracle VM VirtualBox Manager'. This will clear the conflict and you will then be able to open the VM from its new location.

...At that point you can perform a clone if that is what you intend. In my case, no additional effort was required since I no had no further need for the original location of the VM.