Saturday, November 9, 2013

Fatal Error 6: (Buffer too small)

This was my first error message which I received during my lab setup. Where I was trying to install ESXi 5.5 in a Virtual Machine which was running on ESXi 5.5. I am setting up Nested Virtualization, so that I can get more flexibility to use all the Vmware features which are not possible if I use the normal Virtualization (One layer of ESXi) on a single physical server. I will blog about Nested Virtualization in the next blog.

During installation of ESXi 5.5, I received this error message within few seconds.


This error occurred while loading the module /sb.v00 of ESXi 5.5, which indicates some problem with the Image, i.e., the ISO image downloaded from Vmware website (in my case).

I tried downloading again (on Server 2008 R2) and installing it several time with no luck. I used both vSphere Client and Web Client to upload the media to Datastore.

I then downloaded the same image on Windows 8 and uploaded again and this time it worked!!! The problem was with the media but I couldn’t find the reason why it was not working from Server 2008 R2.  I then used Md5Checker software to check the MD5 value and match it with the MD5 value of the image on Vmware Website. I was getting a different MD5 whenever downloaded on Server 2008 R2. This was the first time I faced this issue on Server 2008 R2, it worked perfectly for other ISOs. 

It is very easy to check the MD5 value after downloading the image from any website. VMware provides MD5 value for each download  on the same page

There are many free software available to check MD5 value, I used md5checker (I got this first when I searched, not promoting) and just a drag and drop of the downloaded image provides the MD5 value

Conclusion:  This issue happens because of the bad/corrupted ISO image, either download it again or try downloading it on other machine.


  1. I fix it :
    1) I created a bootable USB with ISO ESXi 5.1.0 U3
    1) I changed the bios to UEFI
    And all works fine.

  2. Make sure your target machine meets the requirements. I tried a newly created USB in a spare laptop just to make sure it would boot and got this error. Realized it was an old mobile Celeron. Since it had booted properly I went and tried it on an actual server - worked fine.