Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I found out how. You can block its startup by unchecking it in msconfig> startup, the MSOSYNC entry, Also it can be blocked in a registry edit:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
Remove the "OfficeSyncProcess" DWord entry
Following a restart the system tray icon did not appear, nor do I see any process for it running. This issue has been discussed in some previous posts related to Office 2010 integration wiht sharepoint and SkyDrive, apparently. I had just not encountered it before having Office 2010 on a machine.