Recover your corrupt VirtualBox .vdi (Virtual Disk Image)

April 9, 2017


Hi guys

I have 3 Windows 10 Professional licenses (Yes, paid licenses). 2 of the licenses are used in two hardware devices & the 3rd one I am using with a VirtualBox VM machine.

My semi server class desktop computer at home has approximately 4.5T storage, consolidated from different disks. My Windows10 VM is frequently factory reset to try out different software (Mostly Oracle software at uncertified environments) & the particular partition on which I had the VM was running out of space & I planned to move the VM & the disks to a different partition with bigger free space.

Scenario: Move “Windows 10” VM from L: drive to M: drive

My nightmare started when the copy process stopped abruptly with Windows popping an error window stating there were read errors while copying disk1.vdi & I attempted again to realize that the disk1.vdi is has bad sectors or clusters.

I hurried to confirm that the VM is still accessible by restarting the VM couple of times & to my greatest pleasure the VM did start, did shutdown properly and I was able to access the Oracle database installation.


A quick googling suggested that an attempt to repair the hard disks using “CHKDSK”, the old utility could fix the .vdi corruptions & without wasting more time I jumped in

At an elevated command prompt issued the command

> chkdsk L: /F

My partition is of 1TB & after 15-16 minutes the chkdsk completed with few messages like fixing some cluster information.

I tried to copy the disk1.vdi once again to M: drive, and this time the copy process managed almost 19GB out of 29.1GB and against present me the read error.

Now, I was left with just one more option in front of me & it was to attempt recover the bad sectors, and there were chances that my virtual disk may get corrupt if the damages are more in numbers. knowing my VM is already Activated by Microsoft, I could try to reinstall Windows in a new virtual disk and retain the license as long as I am still using the other VM files as the id of the machine registered with Microsoft.

Please be informed, if you copy ONLY the vdi file, the activation will be nullified and you will be prompted to activate the copy of the Windows as soon as you start the new VM built using the copied VDI file!

So I proceeded to

>chkdsk L: /F /R

Windows suggested that it may take around 6 hrs for the repair process & I woke up next day morning to read multiple status messages about moving the corrupt sectors to new positions & some errors those could not be repaired.

I hurried to copy the disk once again & even though it seemed like forever, finally I was able to copy the disk1.vdi to M: drive!


So if you ever come across such a situation, give the above a try. If you are not cursed, most probably you will able to recover the virtual disk.



VirtualBox | SATA vs SCSI

July 14, 2015

Recently I tried to build a cloned instance of our production instance over VirtualBox for some emergency issues faced by our inventory module. As this instance was supposed to be only accessed by me, I opted to use my desktop machine for the same. Throughout the last many years I built my own machines, choosing the best available hardware at the time of building them. My current desktop configuration is like following

i7 processor, 16GB memory, 2x1TB 7200 RPM HDD, 2x2TB 5200 RPM HDD, 1x500GB HDD for the OS (Windows 8.1 64Bit)

and throughout the years I built dozens of Virtual Machines using Oracle VirtualBox, mainly for testing un-certified Oracle & other products in a sand-boxed environment, against the crippled VMplayer, VirtualBox’s unrestricted interface supported almost everything I needed from a virtual environment.

So I built my R12 instance, that is around 600GB roughly in size with almost 4.5-5 years of business data, media etc. The following resources were dedicated for the fresh VM

  • 4 processors
  • 10GB memory
  • 40GB fixed size SATA VDI for the Operating System (I used both OEL 5 & OEL 7 64bit)
  • 1.2TB fixed size SATA VDI for the instance files
  • A dedicated D-Link 10/100MB NIC

Once the instance came online, I removed, cancelled all the scheduled concurrent programs, changed the database level parameters like job_queue_processes etc, however the lag experienced throughout the access attempts remained the same. Sometimes the HTML pages took 5-6 minutes to open, forms based modules took 8-10 minutes to open and timeouts were happening, frustrating me to the most possible levels

That is when I decided to give VMPlayer a try, I converted the existing VDI for the OS as vmdk and created a fresh 850 fixed size vmdk for the instance files and attached the same as SCSI to the VM. Did the complete clone process and to my utter surprise, the login page loaded within a minutes once after the instance was started!

This lead me to do various attempts with the fresh instance, I was able to shutdown the instance much faster, forms were opening faster, though LOVs having more than thousands of items were taking more time than anticipated

Once again, I created another fresh VM with VirtualBox and attached the disks created for VMplayer with it and repeated the tests. Well, I got the same performances from the new VM and somehow I came to a conclusion that, both VirtualBox and VMPlayer provide better I/O for SCSI interfaces compared to plain SATA emulators, ironically, the disks were created over SATA drives!

This difference you may not experience with VMs those are not hosting resource hungry applications like Oracle E-Business Suite. So, if you are attempting what I had described above and notice the differences, please update me with comments section.







Windows 10 on Virtual Box | Unable to allocate and lock memory | Virtualbox Guru Meditation error

May 3, 2015

As Microsoft is continuously updating their technical preview for Windows 10, we are sure many of you out there are trying out the latest release 10074, that adds(?) many features. As a precaution, we always use Oracle VirtualBox for testing such releases and never had more issues than with the pre-releases of Windows 10!

One of the regular errors we came across were about “Unable to allocate and lock memory” while the VM started, and gradually pops up another window titled “Guru Meditation”, asking us to view the log files (/me chuckles, when Google can do that for us). We came across a wonderful post, that explains how to resolve this particular dreadful situation with VMs!

and here we are linking the same POST for you! Enjoy and Enjoy your Windows 10 VM



Windows 10 Technical Preview | VirtualBox | Full Screen

April 26, 2015

Trust me, I never try a new OS without testing it thoroughly using Oracle VirtualBox! So is the case with bugs filled Technical Previews of Windows 10 as well. One of the annoyance I had with the builds was, the VirtualBox display driver failing to load/install when the extension packs are installed. That forced me to browse through  multiple VirtuaBox forum entries and there were multiple suggestions (few of them using setextradata switch), and came across one of them suggesting, enabling the Virtual Machine with 3D enabled under display properties.

Does it work? Yes!

Currently I am using VirtualBox 4.3.26, the latest release with Hyper-V disabled over my Windows 8.1 as host and Windows 10 Technical Preview build 10061 as guest OS


Please find below the VM’s display settings

Windows 10 TP Display Settings

Enjoy guys!

for Windows7bugs