i think this procedure can help.(not sure).
1.after botting kali.press ctrl+alt+f3.
2.then you see terminal.press your user and password.
after you have to check your repository by nano.(you can find it google search kali repository).
then update and upgrade your kali machine,type reboot,then it automatically restart.
i think it will help you to solve this problem.
if you can open terminal after log in you can skip 1.continue from 2.