Recover ESX password for different flavor of ESX

ESX Server 3.x:

1. Reboot the ESX Server host.
2. When the GRUB screen appears, press the space bar to stop the server from automatically booting into VMware ESX Server.
3. Use the arrow keys to select Service Console only (troubleshooting mode).
4. Press the a key to modify the kernel arguments (boot options).
5. On the line presented, type a space followed by the word single.
   
6. Press Enter. The server continues to boot into single-user mode.
   
7. When presented with a bash prompt such as sh-2.05b#, type the command passwd and press Enter.
   
8. Follow the prompts to set a new root user password.
   
9. When the password is changed successfully, reboot the host using the command reboot and allow VMware ESX Server to boot normally.

ESX Server 2.x:

1. Reboot the ESX Server Host.
   
2. When the LILO screen appears hit the space bar to stop the server from automatically booting into VMware ESX Server.
   
3. At the LILO prompt select "linux" adding the -s to the end of the line, it should read: linux -s
4. Press Enter. The system begins to boot. The server continues to boot into single-user mode.
   
5. When presented with a bash prompt such as sh-2.05b#, type the command passwd and press Enter.
   
6. Follow the prompts to set a new root user password.

   When the system is finished booting up, you can log in as the root user using the new password. When the password is changed successfully, reboot the host using the command reboot and allow VMware ESX Server to boot normally.

ESX Server 3.5:

A lost Root password cannot be recovered, however it can be reset. The process below outlines how to do this.

1. Power on the host server. When the ESX bootloader selection screen appears, press a to allow you to modify kernel arguments
   
   
   

2. Type single to add the single argument to the kernel arguments and then press enter
   
   
   

3. The host server will now boot
   
   
   

4. Once the host server has booted, you will be presented with a prompt such as sh-2.05b#. At the prompt enter the command passwd and press enter
   
   
   

5. Enter the new Root password. Retype the new password at the prompt. Once changed successfully the all authentication tokens updated successfully message will appear
   
   
   

5. Reboot the host server by typing reboot at the prompt and pressing enter
   

Source

1. http://knowledge.xtravirt.com/hot-tips/esx-3x/11-esx-server-3x/104-recovering-from-a-lost-esx-root-password-in-esx-35.html

2. http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1317898