Install VMware ESXi 4.1 from bootable USB stick

Not all servers nowadays have a DVD player installed. Sometimes it is handy to boot from USB and installing a single VMware ESXi server. Here’s a example how to make the USB stick bootable and install VMware ESXi 4.1 from it by using Windows.


  • Need 1GB USB memory stick or more.
  • Download the VMware ESXi 4.1 ISO named VMware-VMvisor-Installer-4.1.0-260247.x86_64.iso (In this example I used the VMware vSphere Hypervisor version).

Update: The latest version of VMware ESXi is  4.1 Update 1 (VMware-VMvisor-Installer-4.1.0.update1-348481.x86_64.iso). It solves the “Total number of sectors” bug in VMware ESXi 4.1. It is recommend to use this version so the “mod.tgz” workaround isn’t needed anymore!

  • Download Syslinux, can be found by clicking on the following  link. Download the latest Syslinux zip file (when writing this article was the latest).

Update: Also tested Syslinux version 4.03.

Stick the USB stick on a  free USB port on your computer equipped with a Windows OS. For this example I used Windows7 as Operating System. Clear the USB stick and create a partition on it by using the following command’s:

  • Open the command prompt and enter the following commands:
Diskpart (make sure you run diskpart as administrator) 

list disk (list the disk in your system including the USB) 

select disk USB number 


create partition primary 


format fs=fat32 quick 




To make the USB stick bootable:

  • Extract the Syslinux ZIP and browse to the the \syslinux\win32 folder,  execute “syslinux [drive letter USB stick]”, example syslinux f:
  • Mount the ISO  and copy all the content of the VMware ESXi 4.1 ISO to the USB stick. For mounting the ISO, I used ‘Deamon Tools Lite’ tool.
  • Rename the isolinux.cfg file to syslinux.cfg
  • Edit the syslinux.cfg and add ks=usb and on the end of the append line — mod.tgz (beware of the space between and the mod.tgz).

Update: When using VMware ESXi 4.1 Update 1 the mod.tgz line doesn’t need to append!

default menu.c32

menu title VMware VMvisor Boot Menu

timeout 80


label ESXi Installer

menu label ^ESXi Installer

kernel mboot.c32

append vmkboot.gz ks=usb --- vmkernel.gz --- sys.vgz --- cim.vgz --- ienviron.vgz --- install.vgz --- mod.tgz


label ^Boot from local disk

menu label ^Boot from local disk

localboot 0x80

  • Create a ks.cfg file in the root from the UBS stick. For example:
rootpw VMware01

install usb

autopart --firstdisk --overwritevmfs



#Network install type

network --bootproto=static --addvmportgroup=false --device=vmnic0 --ip= --netmask= --gateway=  --nameserver= --hostname=ESXi-01.beerens.local



%firstboot --unsupported --interpreter=busybox

vim-cmd hostsvc/datastore/rename datastore1 "$(hostname -s)-local-storage-1"

  • Copy the syslinux-4.02\com32\mboot\mboot.c32 file the USB stick (overwrite the old file on the USB stick) 
  • Copy the syslinux-4.02\com32\menu\menu.c32 file the USB stick (overwrite the old file on the USB stick)

The bootable VMware ESXi 4.1 stick is ready for use. When booting  the USB stick the following message is displayed “Total number of sectors not a multiple of sectors per track! Add mtools_skip_check=1 to your .mtoolsrc file to skip this test”.


Update: When using VMware ESXi 4.1 Update 1 this bug is fixed. You’re ready to use the USB stick!

On the VMware communities I found the following post. This post states a manual solution by using the following commands:

  • Press ALT-F1
  • Login by using the root account with no password
  • echo “mtools_skip_check=1”>.\mtoolsrc
  • ALT+F2 and return to the orginal Console  window
  • Press ENTER or wait to continue

To automate the above solution read the following blogpost “VMware ESX 4.1 install using Western Digital USB Hard Drive” . By using  this blogpost I created a mod.tgz file by using the following commands from a full installation of VMware ESXi 4.1:

  • Login the VMware ESXi 4.1 console
  • Make a directory in the root for example mkdir temp
  • cd temp
  • mkdir –p etc/vmware/init/init.d/
  • cd etc/vmware/init/init.d/
  • vi 47.mtoolshack
echo "mtools_skip_check=1" >/.mtoolsrc

return ${SUCCESS}

  • Save the fi using the command :wq in VI
  • cd /temp
  • tar czvf mod.tgz etc
  • SCP the file mod.tgz file to the USB stick

The mod.tgz can also downloaded, so the above steps can be skiped. On the end of this article is a download link for the mod.tgz.

The mod.tgz contains an init script which skips the mtools check. Now you’re ready to boot your server with the USB stick and your able to install  VMware ESXi 4.1.                 

Download mod.tgz

Update : When using VMware ESXi 4.1 Update 1 there is no need to add the mod.tgz because this bug is fixed.



58 thoughts on “Install VMware ESXi 4.1 from bootable USB stick”

  1. As TimB I’m getting the same thing – I’m a noob with vmware and it does look to a degree that this works but local disc option doesn’t work once install has been completed.

  2. This is an automatic and unattended installation of vmware esxi, is there a way to do it manually, while booting from usb?

  3. Please note that syslinux does not support USB sticks larger than 2 GB formatted like described above (usually indicated by some error message about it’s config file).

    Either format it with a small FAT partition or use another method to create a proper FAT32 partition > 2 GB.

  4. Update: The latest version of VMware ESXi is 4.1 Update 1 (VMware-VMvisor-Installer-4.1.0.update1-348481.x86_64.iso). It solves the “Total number of sectors” bug in VMware ESXi 4.1. It is recommend to use this version!

  5. This is working nice, except if you want to install from USB to a SD Card in the server, for instance the DELL R710 server.


    “Scripted Install for ESXi.
    You cannot use scripted installation to install ESXi to a USB device.”

    I have tried not entering the line “ks=usb”. It lets me choose to install on the SD Card, but ends up with an error.

    Anyone has an idea how to fix this ? I just want to boot from USB and install onto SD card in server ?

    Thanks in advance!

  6. Be careful when installing with this USB. I have just deleted data on a SAN. Luckily for me it was not data I was going to use.
    So remember to remove all drives and cables to disksystems you want to keep!

    This line from the KS.CFG deletes the first volume the install finds:
    autopart –firstdisk –overwritevmfs

  7. Hi,

    after few hours surfing and testing best tricks and tips I have found this excellent site and howto and this is the only one which works!

    Many thanks

  8. I have followed the directions perfectly as they are posted as of 04/14/2011 and it does not appear to work.

    I get the following output (verbatim):

    SYSLINUX 4.03 2010-10-22 CHS Copyright (C) 1994-2010 H. Peter Anvin et al
    ERROR: No configuration file found
    No DEFAULT or UI configuration directive found!
    boot: _

    I have tried this on both a 500mb and 4GB USB drive, both with the same result.

    Please help!

  9. Very useful post, can you write another one (that will be clearer) for ESXi 4.1 Update 1? Thank you.

  10. Worked for me… Thanks. Only issue I had was installing hypervisor on the wrong drive. Watch the following in sg.cfg. As you/I would expect, it will take the first drive in the boot order and vmfs. My Windows7 drive is gone but it is a test machine.

    autopart –firstdisk –overwritevmfs

  11. Has anyone been able to get this to work installing TO a USB drive from the above created drive? The problem I’ve run into is:
    autopart –firstdisk

    This command will only install to the first non-USB disk. I did an alt-F1 after the install was started up, root with no password, and then fdisk -l to see that my USB drive is listed as:

    Modifying the ks.cfg:
    autopart –disk=/dev/disks/vmhba32:C0:T0:L0:

    Still fails with the installer saying that the drive was not found. Any ideas?

  12. kv1018 – i had the same problem.

    Make sure you disconnect any drives other than the one you want to install too! I installed to my 750GB storage drive.

    Other than that, it worked beautifully.

  13. I tried the method and everything seemed to work till the point the actual installation began. All the modules got loaded, and just when the installation began, I got an error saying
    /sbin/mcopy imagedd.bz2 not found and then after a few seconds, I got another error saying the md5 sums did not match.

    I used the exact method given here. Has anyone else encountered this issue before? Thanks.

  14. problem with mod.tgz download. The above given link downloads a .tar file. I have renamed it simply from mod.tar to mod.tgz and it worked. by the way i got syslinux version 4 and all works the same way.

  15. I followed the instructions to the letter with ESXi 4.1 Update 1, and the install worked perfectly. However, I can’t login to the server, either from the console or the vSphere Client!

    I’ve tried ‘root’ with no password, ‘root + ‘root’, [blank] + ‘root’, ‘root’ + ‘password’, and about a dozen other combinations. I get the same error every time: ‘Cannot complete login due to an incorrect username and password’. I am going nuts! I’ve re-installed 3 times, always with the same result.


  16. Great Article.. Thanks a lot… I got it running on my Dell Precision laptop, which is not on the VMware HCL :). Would not install using CD ROM.

  17. Excellent article! Finally got ESXi 4.1u1 installed after trying couple of other “install from usb”-examples out there which didn’t work.

    Just as a sidenote: Had to use “fs=fat” in diskpart to get the usb stick to boot properly. With “fs=fat32” option I got error message “No DEFAULT or UI configuration directive found” during boot of the usb stick.

    @Pat: What rootpw did you enter in ks.cfg (line 1)?

  18. Thank you for this article!

    This was the only solution how I get it working! I got it running on a Gigabyte GA-MA78LMT-US2H.

  19. Hi,

    I’m trying to install on HP 360G7 server which is 100% compatible with esxi 4.1 u1 gotten from hp website.
    I manage to boot from the usb but after loading the files it returns the following error:

    This system does not have a network interface card that is plugged in, or all network interface cards are already clained. Installation cannot continue as requested.
    I encounter the exact same problem as the one listed here : which didn’t get any replies yet 🙁

    Any ideas? Thx in advance

  20. @Pat
    Regarding the password…it’s VMware01 it’s stated in the 1st line of the ks.cfg. This might be late, but it might help others. This worked great.

Leave a Comment