ESXi Tech Support Mode

1. Log in to your ESXi host at the console.
2. Press Alt+F1 to switch to the console window.
3. Enter unsupported to start the Tech Support Mode login process. Note that no text will appear on the console window.
4. Enter the password for the root user. Tech Support Mode is now active.
5. Complete tasks in Tech Support Mode.
6. Enter the command clear to clear the screen of any residual data from step 5. This may be required by your local security policies.
7. Enter the command exit to exit Tech Support Mode.
8. Press Alt+F2 to return the server to DCUI mode.

1. Connect VMware Infrastructure Client (VI Client) to an ESXi host or a VirtualCenter Server.
2. Browse to a host in the inventory list.
3. Click the Configuration tab.
4. Click the Advanced Settings link.
5. Click VMkernel in the left-hand pane.
6. In the list of parameters, deselect VMkernel.Boot.techSupportMode.
7. Restart the ESXi host. Before restarting the host, you should shut down virtual machines on that host or migrate them to another host using vMotion or cold migration.

KB: http://kb.vmware.com/kb/1003677