Thanks so much for responding! Sorry, but I don't think I explained very well. What I meant to say is I have never seen a Process Name listed in Activity Monitor that had a PID number listed in the actual name display so this one caught my attention. All other process names have just the name such as 'IMRemoteURLConnectionAgent' or 'ads_stores' etc. But instead of being listed as just 'QuickLookUIService' like all other processes, it is listed as 'QuickLookUIService (PID 438).' It just seemed odd that this is the only process I've ever noticed that has a PID number in parenthesis added to the process name. Plus, it seemed ironic that 438 is also a TCP port that made me wonder if my com.apple.QuickLook.thumbnailcache file was being remotely tapped via port 438 (Recently learned that Quick Look can be a major security risk). Does that make better sense? Don't mean to sound paranoid, but it seems that if someone can gain access to the Quick Look thumbnail cache, they pretty much have it all.