Mojave and High Sierra users might can not launch CleanMyMac 3.10.x and CleanMyMac X 4.x.x. In another case, CleanMyMac just keep crashing when start launching. Here below is a quick steps to fix.
That disable the System Integrity Protection (SIP) would fix the related issues.
Open Terminal, and enter the following command line.
sudo codesign --force --deep --sign - /Applications/CleanMyMac\ X.app
You then might be asked for administrator password (the login password).
If you face any problems relative to xcode, just simply Enter the following before the above command line.