Category: Virtual Machines

Oct 14 2010

VirtualBox tip: Restore vs Delete Snapshot

Restore snapshot will restore to the state of the snapshot you select.  That makes sense.

Delete snapshot does NOT make sense.  Delete snapshot MERGES the snapshot to its parent shapshot.  (It IS deleted in that it is no longer needed and therefore removed but it really should have been called Merge Snapshot.)

Oct 01 2010

To enable internal networking using DHCP on multiple VirtualBox VMs do this…

VirtualBox rocks.   I needed to setup 3 virtual box machines so that they would have there own little network.  This is a good thing because the other methods had some limitations… with NAT the VMs cannot communicate with each other.  Bridged Networking will work fine but requires that the bridged network adapter be on a real network which for my situation is not always feasible.  Host-only probably WOULD work in this scenario but it more complex. 

Bottom line…internal allows the VMs to communicate while NOT requiring the presence of a real network and without being overly complex. 

To setup do the following…

from the command line setup a DHCP Server for your internal network by using the following command:

VBoxManage dhcpserver add --netname intnet --ip 
--netmask --lowerip --upperip


The switch setting here are pretty obvious.  The ip switch is the ip address that will be assigned to the DHCP server.  The netmask switch is the subnet mask that will be used by the DHCP server and assigned to the clients.  lowerip and upperip is the range of leased addresses issued by the DHCP server.  Enable activates the server. 

That will create a new DHCP server that will start and lease addresses when you start the VMs that you want to be on the internal network.

Next, on each VM you want to be on the internal network, open the network settings and for at least one of the NICs set it to use Internal as the network type.  Notice that the internal network name is already set to intnet (which is the network for which we created the DHCP server.)

Now when you start each vm they will be automatically added to this private internal network and can communicate with each other.

Happy VMing.


Jul 16 2010

If you are moving a Windows 7 physical machine to a VirtualBox VM don’t forget to …

Just spent all day resolving this one but in the end it was surprisingly simple.

I think after all that I did…I COULD have done just these two steps…

I was getting BSOD when attempting to boot.  The STOP code was 0x0000007b.  This stop code means inaccessible boot device.

I should have done the following. .  Before making an image of your Windows 7 that you want to virtualize follow the steps in the knowledge base article.  On my machine the Atapi.sys, Intelide.sys, Pciide.sys, and Pciidex.sys drivers were already in the %SystemRoot%\System32\Drivers folder.  So you might be able to skip that step.  (The main step, merge the REG file into windows, is required).  For more on this see this virtualbox page.

(Incidentally, having Search Everything sure helps with finding files on a Windows system.  Get it from  It indexes EVERY SINGLE FILE on your system so you can search by filename for any file.  It does NOT index the content of those files…only file names.)

Next when creating the new virtualbox I should have added a SATA disk controller and put my c-drive under it rather than the IDE controller that VirtualBox created by default.  Duh!

That fixed me up.


Jan 04 2010

Something to try if your new VirtualBox VM is blue screening

I have on a few occasions created a Virtual Machine for VirtualBox by restoring an image from a physical machine backup.  More often than not this VM will not start but, rather, blue screens and shuts down or reboots.

This happens because old physical hardware does not match the new virtual hardware that runs inside the VM.   When device drivers load for non-existing or unexpected hardware Windows replies with a BSOD.

I recently discovered way to get around this that worked for me.  This may or may not work for you but it is worth a try.

  1. Start the VM in safe mode.  (Hit the F8 Key until the boot menu comes up and choose the safe-mode option.)
  2. If the VM starts in safe mode…great.  If not, I can’t help you.
  3. In safe mode edit your Environment Variables and add the following:  DEVMGR_SHOW_NONPRESENT_DEVICES.  Set the Value = 1.
    (To Edit Environment Variables … Right Click My Computer and choose Properties.  Click the Advance tab.  Click the Environment Variables button)
  4. Now start Device Manager.  (Start/Run devmgmt.msc)  Because of what you did in step 3, you will see a lot of devices that are greyed out or ghosted.  Delete all of them.  Close Device Manager.
  5. Now Disable all non-Microsoft startup items.  (Start/Run msconfig).
  6. Restart your VM.  If you can startup while NOT in safe mode…congratulations.  It worked.

PS.  You can re-enable your startup items again.  If you start to BSOD then disable them again and re-enable them one at a time till you find the bad guy.


EDIT – I tried this with one client but it didn’t work.  No missing devices were found in the device manager.  The machine would blue-screen and re-boot.  But the blue screen happened too quickly to actually see the blue screen error in the virtual machine.  To configure the virtual machine to not reboot after blue-screening do the following:

  1. Open up System Properties.  (Right Click on My Computer and choose Properties).
  2. Under Startup and Recovery click Settings.
  3. Clear the checkbox that says Automatically Restart.

After setting this I was able to reboot the virtual machine and after googling the blue-screen error I was able to solve the problem.


May 15 2009

Converting a Virtual PC to a Virtual Box – P 5: Copy your VPC System Image to another computer.

Copy the VPC image you just created to another computer.

To do this you will have to boot back into Windows on the VPC you are converting.


  1. You should now be back in Windows in the VPC you are converting (if you followed STEP 4.)
  2. Browse to the new drive you created in PART 2 and you should see your freshly minted drive IMAGE there.
  3. You have to get that file (or files) copied off of the VPC onto a REAL PC. To do this you can use SHARED FOLDER feature of VPC or you can use a network folder.
  4. IMPORTANT NOTE – i find that SHARED FOLDERS are very unreliable. Many times when I use this feature of VPC I get WRITE errors. Use a network if you can. (One good reason to switch to VirtualBox.)
  5. Shut down your Virtual PC.

Now you are ready to begin transferring your disk image to a shiny new VirtualBox.


A video demo of this step.


May 15 2009

Converting a Virtual PC to a VirtualBox – P 4: Create an image of your system drive.

Create an image of your system drive.

If you followed the last steps of PART 3 you should have now booted into your imaging software.


  1. Use your imaging software to create an image of your VPC.
  2. Be sure that the image is created onto new Hard Drive that your created in PART 2
  3. After the system drive is imaged…reboot to the PC…to do this use the VPC CD menu to unmount the CD or ISO.
  4. Boot Back into Windows.

You have to boot back into windows because you have to get the IMAGE you just created OUT of the Virtual PC and onto a REAL PC. More on that in the next step.


A video demo of this step.


May 15 2009

Converting a Virtual PC to a VirtualBox – P 3: Start VPC, format the new HD, remove Virtual Machine Additions

Start VPC, format the new HD, remove Virtual Machine Additions

You can’t save the image of your system drive until the new hard drive is formatted

and you VPC Machine Additions can conflict with the VBox Machine Additions…so to avoid problems let’s remove them.


  1. Select and click Start for the VPC you want to convert.
  2. After booting use the Windows Disk Management tool to format your drive. To get to it right click on My Computer and choose Manage. (New versions of windows can type Disk Management into the Search bar.)
  3. Create a partition on the new drive and format it using the defaults.
  4. Add a New Hard Drive to your Virtual PC using the usual methods…hint…right click the new drive…after creating the partition…right click to format.
  5. After the disk is formatted…shutdown the disk manager and remove the VPC Virtual Machine Additions. Do this using Control Panel/Add Remove Programs. DO NOT RESTART.
  6. IMPORTANT: Mount the CD drive or ISO image that has your bootable disk. You do this by clicking the Settings menu of VPC and clicking the CD menu.
  7. Restart your PC. The VPC should start up into the imaging software…NOT windows.

When you restart the software your machine should restart into the Imaging Software you use. I use Image for Windows which is very effective and pretty inexpensive. That comes with bootable imaging software called Image for Dos and Image for Linux. I use the Image for Linux software. But you can use whatever you want or already have. If you don’t have imaging software check out the Ultimate Boot CD which is freeware and has imaging software included. But don’t ask me for help using it…I use Image for Windows.


A video demo of this step.


May 15 2009

Converting a Virtual PC to a VirtualBox – P 2: Add a new virtual drive to your PC

Add a new virtual drive to your PC

This will be the target drive for your VPC image created in a later step


  1. Start Virtual PC
  2. Click on the VPC you want to convert.
  3. Click on Settings.
  4. Add a New Hard Drive to your Virtual PC using the usual methods

This new hard drive will be used as the target drive for imaging the main System Drive of your PC.


A video demo of this step.


May 15 2009

Converting a Virtual PC to a VirtualBox – P 1: Getting Started

Getting Started

This post does not have content yet but since the serializer uses post date/time I am putting this in as a stub.

Why convert.
Tools you will need.