Jul 04, 2014 There is no “safest” uninstalling program – any kind of general uninstaller app should never be used at all. When uninstalling software, you should ONLY use the uninstaller provided by the developer of the software being removed. In the case of avast!, open the app, and it can removed through a menu item in the avast! I didn't realise it the first time and I think it installed Avast free antivirus on my computer. I already have virus protection that I like and don't want to change. I started a full scan just to be safe and then I thought I should probably just uninstall it now before it does anything bad if at all.
Something that doesn't exist can't be blocked. A virus is self-propagating software. It requires no user interaction to spread. These have yet to exist in any form in OS X/macOS. Every type of potential malware out there are Trojans. Something the user has to knowingly, or unknowingly install. It can't get on your Mac on its own.
Why Avast Is Bad
Safe Mac Says Avast Is Bad Software Free
Avast, and any other such software is a complete waste of time and system resources. They can't block Trojans (of which all adware falls under the same type of installation category). The AV software can't know something is dangerous until you install it. And it's pretty useless to tell you the software is bad after the fact.
I have seen multiple topics on these forums where the user has two, or even three types of AV software on their barely-functioning Macs, and they're loaded with adware and other junk. That should give you an idea how pointless AV software is.
macOS has multiple layers of protection built-in to it. It needs no help protecting itself. If anything happens to get by Apple's defenses, it will get by third party junk, too.