There is only one file type that uses the .MXC2 extension:
MAGIX Cache File
Cache file created by MAGIX software; contains metadata used to speed up the process of generating previews of media files within folders and subfolders; commonly seen with the name mxfilerelatedcache.mxc2.
MXC2 files are automatically created when users browse through folders with the Media Pool built-in program.
Updated: December 12, 2015