usermod and processes

[TrekkingBob]

I am trying to change the username from rock64 to something more personal. 

I have searched this forum and ubuntu's and in general. I am also running Xenial-Mate latest stable from the wiki. Fresh install to microSD.

If it helps at all, I've created a temp user called temp. 

For reference, I've mainly followed this write up done on askubuntu.com.

So I have made sure to not be logged into rock64 user when running the

Code:

sudo usermod -l rock64 <newuser>

But I get this message
"user rock64 is currently used by process 2245" even after having ran the command
 

Code:

sudo kill 2245

I have also been running these commands through the CLI when you hit ctl-alt-f1 at loggin.