getting sudo: unable to change to sudoers gid: Operation not permitted

Hi,

I moved /home directory to /home.bak and restarted machine, since then I am unable to login to the account.
when I log in using guest user log in and trying to

mv /home.bak /home I am getting the below error

sudo: unable to change to sudoers gid: Operation not permitted

Please suggest the solution.

Thanks,
Megh