Norton 21.6 not releasing memory

I just updated my PC with the latest windows updates anbd Norton and left ot on unattended for a few days.

I was pleased to see a message fro Norton saying my system was all tuned up, but then saw in Task manager that I was using 6GB of memory and all I had was task manager and Chrome running

It was reporting that n360.exe (32) had used 79 hours of CPU tme and was still occupying over 1GB of memory.  svchost.exe was actually using even more

I would have expected the software to release its memory if it had finished tasks such as full system scans, defragmenting the disk and cleaning out temporary files etc.

How can I safely erstart Norton to kill this huge process?