CCleaner a widely used utility was hacked opening a backdoor and allowing Malware to be attached to some seemingly legitimate versions of the software. As a precaution to our clients (Those under our IDMax protection) we set a global removal of any older versions. There are updated versions that are not susceptible and the 64Bit versions are not effected by this specific issue.   If you would like more info read below: Forbes – Hackers Hid Backdoor Avast Blog Response / Update