- Root Permission
- File Explorer (with root access)
Using the root file explorer, go to this directory : /data/system/ . Then, delete the file Accounts.db
Here's a little explanation on this, the moment you created/registered a Google account on your phone the file Accounts.db will be auto generated. This is a database file which carries all the accounts you have registered with the phone. The moment you delete it, it's as if the account was never registered. Why does Google made it this way? Because if they'll integrate this in an application, the users can just simply clear the data to remove the account.