Cannot Start VirtualBox Virtual Machine after an Upgrade

Having upgraded Oracle Virtualbox on a Windows host, I found that I could not start any Virtual Machine instances. VirtualBox displays a dialogue window with the error message shown below,

Examining the virtual machine log file, i.e., Logs\VBoxHardening.log in the Virtual Machine instance directory, I found the following error message near the end of the log file,

1660.6c38: supR3HardenedVmProcessInit: Opening vboxdrv stub...
1660.6c38: Error opening VBoxDrvStub:  STATUS_OBJECT_NAME_NOT_FOUND
1660.6c38: supR3HardenedWinReadErrorInfoDevice: NtCreateFile -> 0xc0000034
1660.6c38: Error -101 in supR3HardenedWinReSpawn! (enmWhat=3)
1660.6c38: NtCreateFile(\Device\VBoxDrvStub) failed: 0xc0000034 STATUS_OBJECT_NAME_NOT_FOUND (0 retries)

Driver is probably stuck stopping/starting. Try 'sc.exe query vboxdrv' to get more information about its state. Rebooting may actually help.

The message indicates that Windows service vboxdrv, i.e., the Virtual Box Driver has some problem. Following the advice in the log, I issue sc.exe query vboxdrv in a Windows Command Prompt window,

C:\>sc start vboxdrv
[SC] StartService: OpenService FAILED 1060:

The specified service does not exist as an installed service.
C:\>

which indicates that Windows service vboxdrv does not exist. To fix the issue, I reinstalled the driver vboxdrv from the directory C:\Program Files\Oracle\VirtualBox\drivers\vboxdrv. From the Windows GUI, you can right click the VBoxDrv.inf and choose "install".
If the installation is successful and you query the driver status again, you should see something similar below,

C:\>sc query vboxdrv

SERVICE_NAME: vboxdrv
        TYPE               : 1  KERNEL_DRIVER
        STATE              : 4  RUNNING
                                (STOPPABLE, NOT_PAUSABLE, IGNORES_SHUTDOWN)
        WIN32_EXIT_CODE    : 0  (0x0)
        SERVICE_EXIT_CODE  : 0  (0x0)
        CHECKPOINT         : 0x0
        WAIT_HINT          : 0x0
C:\>

Now I can launch the virtual machine instances.

Default Desktop Crashes in Ubuntu 13.10 (Saucy) as a VM VirtualBox Guest

I created a guest instance using Ubuntu 13.10 (Saucy) in Oracle VM VirtualBox. When I log in using the default Ubuntu Desktop environment, what I got was a nearly blackscreen after a "compiz crashed" message. My suspicion was that the video card is too  primitive and did not have a reasonable OpenGL support.

To fix the issue, I installed Gnome desktop and logged without any problem in using the Gnome Desktop environment. Since the default desktop environment crashes and I could not get a terminal window to do anything, I had to exit to the console to do the installation. The steps are as follows,

1. Press CTRL-ALT-F1 to switch to the console screen
2. Log in on the console screen
3. Install Gnome desktop environment, by running
         $ sudo apt-get install gnome
4. Kill and restart X or simply reboot the machine, by running
         $ sudo reboot
5. When the Graphical Login screen appears, click on the little
   icon to the right of the user name, and choose any of Gnome
   desktop environment, (Gnome Classic, Gnome Classic ...)
6. Then log in. 

You should be in without any problem.

Convert VirtualBox VDI to VMWare VMDK

You can run virtual machine instances created in one virtualization software in another. QEMU is a good tool to do this. The following example converts a VirtualBox VDI file to a VMDK file that can be loaded in VMWare.

I did the conversion on a Windows host. You can download the precompiled Windows binaries of QEMU, provided by Prashant Satish,  or those provided by Eric Lassauge.

The procedure is the same in Linux hosts.

1. To convert VirtualBox virtual appliance to a VMDK file.
   

   qemu-img convert  virtualbox.vdi  -O vmdk vmware.vmdk

2. If you have VMWare Workstation or more luxury version, you can start with creating a new virtual machine. During the process, you have the option of selecting an "existing disk". In this case, you simply select the .vmdk file.
   
   However, I would like to stick to the free VMWare Player that does not provide the option of selecting an "existing disk". I have to use a workaround.
   
   Start VMWare Player, then create a new virtual machine, for instance, a virtual machine called "vboxvmware".  You must select "I will install the operating system later." option as the two images show. 
   
   
   
   
   
   
   
   Since you created or downloaded the VirtualBox virtual machine, you should know what guest operating system it is and what memory capacity is allocated. Choose them accordingly.
   
   
   
   
   
   
   
   Next step, choose the option of "Store Virtual Disk as a Single File".
   
   
   
   
   Upon confirming your choice, you will see that the virtual machine is created.
   
   
   
   
   
   The last step is to edit the VMWare virtual machine configuration file (.vmx file). Go to the directory where the virtual machine is located, locate the .vmx file, and edit the file using your favorite text editor. In the editor, locate the line of "scsi0:0.fileName = ..." and replace the virtual disk file by the .vmdk file previously converted using QEMU. Note that when you edit the file, make sure the path of the .vmdk file is correct if it is not copied to the directory. Then, you can safely remove the vboxvwmare.vmdk file that your virtual machine does not really use. You can then safely launch the virtual machine from the summary screen.