Root - How to remove one of the superuser app? I rooted my phone a month ago and downloaded the SuperUser app yesterday.  

However, when I use the app SuperSU, it is not running and it said i need to update a file. I could not update it.

What can I do? How can I remove SuperUser?
Run the SuperSU app. If you’ve uninstalled it for whichever reason, all you need to do is Reinstall it from the Google Play Store.
Click on the Settings tab on the top right corner, and then click Full Unroot. Confirm with 'Continue'.
Once this operation is done, which takes a few minutes, you can reboot your Android.
Uninstall SuperSU.( If Exists.....)