Why does Avast uninstall so easily& installs over remnants of other AV program?

[ecbritz]

I bought Avast Pro for three computers because of the SafeZone, Sandbox and Boot-time scan functions. However, I must admit that I have always distrusted Avast slightly because it uninstalls so easily compared to for instance Kaspersky, which needs a special "kav-remover" program to be completely uninstalled. Even more alarming is the fact that Avast will install even if there are remnants of another anti-virus program remaining in the computer. Kasperski, at least, will never install if it detects the same remnants. The impression this leaves is that Avast does not reach as deeply into the system and does scan as thoroughly as a "heavyweight" AV program -- Kaspersky, Norton, and the like. I never play around with torrents today. But from experiments in my early youth I can say that Kasperski detected and removed any virus or malware attached to any torrent download -- immediately and without fail. The risk was such that I did not trust Avast to save me from these dangerous waters, after discovering the free and easy way Avast installed-and-uninstalled. What do the experts say about this? What does Avast's relative ease of installation and uninstallation mean in terms of it effectiveness? 

[Driver8]

This is an interesting idea.  I have not seen anyone comment on a piece of software being too easy to remove before.  It causes one to think.  I am no expert, but I don't know why one would assume that there is a relationship between ease of uninstalling and the effectiveness of an anti-malware program.  Just to play devil's advocate, perhaps one could look at it this way ... maybe Avast's programmers are more skilled in writing their removal routines and that the coders for other programs such as Kaspersky just don't know how to write a complete removal routine.  Besides, Avast does offer an uninstall tool to help clean-up.  You can see it at http://www.avast.com/uninstall-utility.  I have been using this tool as I have been working to resolve problems with the latest version of AIS and it does a good job of totally cleaning out the remnants of the Avast.

I do know what you are saying about trusting a program however.  Trust is an interesting thing when applied to computers and software.  I have trusted Avast and Kaspersky on and off over the years for various reason.

[bob3160]

You should never install one AV without first totally removing what's current on you computer.
Sooner or later there will be a conflict if that rule isn't followed.
avast! is no exception and has it's own removal tool:
http://www.avast.com/uninstall-utility

[RejZoR]

If you need special tool to remove it it just means their uninstaller is a piece of hunk. It's also not avast!'s job to babysit others bad work. It's their job to make uninstallers work right.

[ecbritz]

The "heavyweight" German anti-virus program Avira, touted to be amongst the very best AV engineering you can buy, also played a role in my decision to buy Avast Pro for all three desktop computers I have in use -- despite the doubts I still have about Avast. I paid for a five computer Avira license recently, hoping to forget about virus problems with my five computers for a year. Once bought, Avira would not install. I wrote to Avira and was asked to create and send a kind of "trace evidence file", using a tool provided by the company. Avira later reported back that there were remnants of an old Avast installation preventing an Avira installation. They provided me with another software tool to remove these remnants and other possible impediments to the installation of the product I had bought. After using Avira for a month or two, the program reported "hidden virusses" it could not remove. It also stalled on encountering these unremovable hidden virusses. There was apparently a special Avira tool I could download for the hidden virusses. But I had become fed-up with the difficult-to-use interface and the constant crises. The idea that the Avira stopped working on being confronted with the hidden virusses, really put me off. I suddenly remembered that Avast could do a boot-time scan, more effective than the Windows Safe Mode scan usually recommended for hidden virusses. I uninstalled Avira, installed a trial version of Avast Pro, did a boot-time scan and hey presto! Avast discovered and removed the hidden virusses. Since then I have put my wavering trust in Avast. Wavering because its such a "slick" product and because it has definitely installed with remnants of another, previous AV product still on one of my computers. I discovered this in a comparative experiment I did with Kaspersky. (It was not the latest Avast 7 version though.)