In the past, when I watched a video on You-Tube or on another video streaming site.
I would see a large size video file (5MB-15MB or more) if I searched the hidden Temporary Internet Files folder, .
I used to have a large chunk file from YouTube or shared videos site downloaded in my TIF folder. Now, a video file is broken into many 1,781,760 kbs files or many 1.7MB files.
At first, I thought it was Windows firewall and defender or my AV problem. Now I know someone out there has the same problem. I think it could b Flash player, Windows updates that MS installed secretly or Windows Defender.
I am using VideoCacheView from nirsoft to find my vids but now there aren't any.
Some people recommended using free version of Youtube Downloader.
BTW read the comments of Youtube Downloader before downloading. Thanks.
Read this
Has YouTube canned downloading file to Win7 TIF folder?