This file is a harmful and undesirable program. Probably virus. It's recommended to delete it.
What is mmx.exe Windows startup process
File name: mmx.exe
Program name: XiD
Description: ANALOGX TROJAN
Information added by: fotografos at 01 January 2009
Hint: If mmx.exe file is a virus or trojan, we recommend to use a antivirus software or registry cleaner.