the vRealize Operations Manager 6.0 server had been locked out in one of our customer environment and the reason was that he forgot the password and he tried to login several times .
This is the process we used to unlock the root account.
Open up a console session to the VM
Press Alt + F1 and try to login as root
You can see by the screenshot above that someone has tried many unsuccessful attempts to access the root account and subsequently it has been locked by the operating system.
Reboot the virtual machine
choose the 2nd line and use the following string
Now hit Enter, and the machine will now boot into a bash shell
Run the following command to unlock the root account
pam_tally2 –user=root –reset
If it works, you should see something similar to the following screenshot.
but you still need to change your passw0rd because you forget it therefore use this command to reset it
and Now you can change the root password and restart your VM and try login again.