After I installed LN 8.5 each time when I run LN8.5 the sametime run also. I don't like this because I don't use it. So if you want to disable it you should add/change variable in notes.ini
IM_DISABLED=1 IM_DISABLE=1 IM_SHOW_STATUS=1 com.ibm.collaboration.realtime.application/useSystemTray=false
Please notice 2 variations of IM_DISABLED / IM_DISABLE, it depends of version of LN you have, so if one does not work for you, try another setting.