System Volume Root Usage is 82% Antivirus not updating

So, i also had an issue with my readynas no updating the Antivirus. 

Long story very short it was a load of Junk files from Plex, i had a 82% Root Usage.

Im a Linux nube so I will keep this easy for the other Nubes. if you want to use Windows then install a program called putty.

You will need to have SSH switched on from your Option list on the ready nas

in Putty then use the server ip for example
192.168.1.10

log in as root not admin

then use the ready nas server password

this opens up a terminal.

As you are logged in as the root
cd  /

to show contents
ls -1

 If you have the same issue with Crap from Plex then you can see a load of junkchunk-stream0-00149.m4s

display files size in human form
du -h

mass delete of files
for example
chunk-stream0-00149.m4s
chunk-stream0-00150.m4s
chunk-stream0-00151.m4s

rm -rf chunk-stream0*

Caution think before you delete.

Then dis engaged the antivirus, restarted the system then re engaged the Antivirus and all was good. No more root usage warnings