- Connect the console cable to the Fortigate and fire up your favorite terminal emulator
- Reboot the firewall unit.
- At the console login prompt, type in "maintainer" as the userid.
- Type in bcpbFGTxxxxxxxxxxxxx as the password. xxxxxxxxxxxxx will be the S/N of the Fortigate. The serial number is case sensitive so for example you should use FGT60B, not FGT60b.
- After logging in, change the admin password:
Heads up: You have to type the userid and password within a few seconds of the login prompt first appearing. If you take too much time you should reboot the firewall again.
References : http://firewallguru.blogspot.com/2009/08/resetting-lost-fortigate-admin-password.html