I am using Oracle Virtual Box version 4.2.16 r86992. Everything was fine until yesterday shutdown. Today, it shows inaccessible and throws this error:
Runtim
This is going to sound stupid but try to reinstall VB. It may work.
I faced the same problem and I resolved by doing following in Oracle Virtual box 4.3.28 with Ubuntu 14.04 LTS, when Virtual box VM was closed.
Removed ubuntu.vbox to another folder outside virtual box folder
removed -prev from file ubuntu.vbox-prev
start oracle virtualbox, it works excellent.
This normally happens if the host OS crashes or you pull the plug on it, leaving the .vbox file unsaved.
In the location:
C:\Users\xxxxxxx\VirtualBox VMs\vBoxxxxXubuntu_Beta\
you should find two files:
vBoxxxxXubuntu_Beta.vbox-prev
vBoxxxxXubuntu_Beta.vbox-tmp
Copy vBoxxxxXubuntu_Beta.vbox-prev
to vBoxxxxXubuntu_Beta.vbox
.
Select vBoxxxxXubuntu_Beta.vbox
, in the VBox manager, right click, and then left click on refresh.
Observe that it now shows Powered Off.
Now you are good to go.
I've faced the same issue using CentOs 6.8 on a VirtualBox 5.1 installed in Windows 7 and AjayKumarBasuthkar's solution worked perfectly for me:
The virtual box files with extension .vbox contain metadata the virtualbox hypervisor requires to resolve the guest virtual OS' configuration.
If the main .vbox file is corrupted (i.e. reporting that it is empty) then use the backup .vbox-prev file to recover the contents of the original file.
Do this by renaming the empty .vbox files a temporary name (e.g. rename originalVM.vbox to originalVM-empty.vbox).
Then make a copy of the backup file originalVM.vbox-prev, where the copy will have the same name as the original but with the word "copy" appended to it (i.e. originalVM.vbox-prev is renamed to originalVM (copy).vbox-prev).
It is important to retain the original backup .vbox-prev file it should not be altered or itself renamed.
Now go rename the copy of the newly created .vbox-prev file originalVM (copy).vbox-prev to the original name of the empty .vbox file and be mindful to also change it extension from .vbox-prev back to just .vbox.
That is rename originalVM (copy).vbox-prev back to originalVM.vbox. Now that this is done you may add the .vbox file (guest os) back into the VBOX hypervisor.
This will recover the state and snapshot of the "inaccessible" guest VM. Now delete the original empty .vbox file.
VirtualBox 4.3 is released and could it be that you've updated or there was some issues while updating?
In any case if you are not able to bring up the Virtualbox, remember to backup the VirutalBox VMs folder and going for a fresh install should be the best way forward.