Replay Media Catcher watches your network traffic for anything that "looks" like media. Sometimes, Replay Media Catcher will erroneously identify other traffic as media.  Other software packages that use automatic update mechanisms might be picked up by RMC5.  A few frequent offenders are avast.com, mozilla.net,  garmin.com and microsoftupdate.com, and they will leave cryptically named files in RMC5, often with a MP3 file extension . The easy solution is to add these sites to our Ad Blocker feature. so that they are not recorded.
http://applian.com/replay-media-catcher/support/user_guide5#adblock 
Here is a video for how it works: 
http://applian.com/support/videos/replay-media-catcher/adblock_5