.MCO File Extension
File TypeLive Messenger Winks File
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is an MCO file?
Contains Flash-based animations, called Winks, that can be sent using Windows Live Messenger (formerly MSN Messenger); similar to sending an emoticon, but can be a much larger animation.
Winks may be installed using Messenger Jump! MSN Winks Installer or MSN BackUp.
NOTE: Windows Live Messenger was discontinued in 2013 and has moved to Skype.