It has come to my attention that CCleaner (owned by Avast) is engaging in highly unethical behaviour in that it uses pre-checked options in its updater to install by default Avast Free AV, even on systems with resident protection already provided by reputable AVs such as Microsoft Security Essentials (MSE) and Panda Free AV. I speak from personal experience, and from communications from others. I can provide links to corroborate this claim.
This is not only unethical but unsafe. Having two AVs running in real time degrades system security, as Avast must well know. There really is no acceptable defense for this practise. I speak as a moderator of several security foums over the years, including Calendar of Updates and Spywarehammer, among others.
I was a user and supporter of Avast almost from its very first versions. I promoted it as a credible free alternative to the paid AVs over a decade ago. I am a current user of CCleaner, but am very concerned by reports of current Avast/CCleaner users that CCleaner is auto-updating without explicit permission.
In my mind,reputable security programs do not auto-update without explicit permission. They do not install new AVs via pre-checked options in non-security programs. Particularly if that system already has reputable AV protection from another vendor.
Avast,you have a lot to answer for here. I have always trusted Avast and CCleaner until recently.