I'm having the same problem. Close the game and get the 5899mb patch which never completes. I left it run for 4 hours, it reached 75% then closed itself with an error message that also closed itself before I could even check it.
Yup, i get the same thing every time i exit STO for the past 3 days and have lost 10gigs, and will problly never see the 10gigs again. Last night it was patching, i minimized to system tray, looked at it about 3 hours later and it was gone, thinking it has completed, i didnt get no error message but i no it didnt work cuz i loged in and loged off and exited and the launcher still reopens everytime wanting to download a 5899mb patch, but at this point i just exit the launcher be4 the patch can start, and im just gunna wait for the launch of LOR on the 21st.
"This is Fleet Commander BumBle!..
Vice Admiral of the U.S.S. Prometheus!..
I order you to lower your shields and weapons or ill be forced to fire upon you!!!"