I have a security-cam file on a USB stick which I am not able to open. I got this from my neighbor as I don't have a security-cam. It has 2 files on the stick one is a VLC app file (exe file), the other an MP4 FILE. I open the MP4 file and get error:
"This file isn't playable. That might be because the file type is unsupported, the file extension is incorrect, or the file is corrupt."
Please help.

 

Vlc is a media player, download VLC media player ( it has an orange traffic cone as an icon)and see if you can open it.
Most CCTV files are in H264 compression.

 

You're probably missing the codec. The easiest way is usually to find out what brand security camera it is and find out if they have a player. Plan B would be as mentioned above, try to open it with VLC and it if it fails then try to figure out what codec it needs that is missing. Sometimes it works to upload the file to a service like YouTube.