Q: Why I can't install Avast antivirus on my macbook and it appears this message "Sophos antivirus has been detected. To install the avast! product, please uninstall the incompatible software first." After I uninstall it appears again.

Your computer likely has an Adware or other product installed; a virus is unlikely.

Both antivirus brands should be completely installed, then only considered if you

run a BootCamp (AV in Windows partition) or get content online and want to filter

out Windows viri before sending content on to Windows users.

To look through this site and see how an Adware situation may be affecting your

computer: Adware removal guide - thesafemac: http://www.thesafemac.com/arg/

There is an Adware Removal Tool (a script that runs to locate & remove most

adware types) as a download from the above site, with its own link. Also, note

the rest of TheSafeMac site, in that several 'Tech Guides' of info are in there.

http://www.thesafemac.com/tech-guides/

Also you could take a look into some of the more easily seen indicators of adware

or other bits of other bad ware you may have encountered; a good tool that can

generate a report of the basic system, which could be copy/pasted into a forum so

those who have experience or know what the bits of bad software are, can help to

remove them. Processes and methods of removing adware and other items do

take a bit of time and steps. However, you can help discover some of the otherwise

unknown and non-virus issues your Mac likely has installed...

This is a software that generates a report of the system; more thorough methods

requiring the use of OS X unix underpinnings (via Terminal commands) are often

beyond the GUI experience of most novice users of modern computers; so a

software such as Etrecheck is often an easy way to look into some of the many

items that may be appear, in a report, to be afflicting your computer.

http://www.etresoft.com/etrecheck

{note the 'read more about' link in the download page, and read it}

These items appear to have been helpful to may who have found issue in their

Mac OS X, and the information and methods to deal with these problems is free.

The contributors of both sites above are long-standing members of ASC forum

discussions. A more technical minded and detail oriented effort, of another ASC

contributor by the name of Linc Davis, may see your post and he looks into this

kind of matter in a level that will challenge your ability to learn about your OS X.

Hopefully you can identify the issue, and then apply the correct methods of

removal to gain your computer system & performance back. Then, read up

(not commercials) before buying into third-party additions to your Mac OS X.

The system can take care of itself, for the most part.

Good luck & happy computing!

edited 2x

You don't have a virus - you have serious overkill for a/v software. If you've Sophos installed then you don't need avast! You likely don't need either of them.

See -> http://www.thesafemac.com/mmg/.

Clinton

MacBook Pro (15-inch Late 2011), OS Mavericks 10.9.4, 16GB Crucial RAM, Crucial M500 960GB SSD, 27” Apple Thunderbolt Display

thypp wrote:

 

I think my macbook may has a virus because the pop-up are always show even I already blocked them. So, I downloaded Sophos Antivirus but it couldn't find the virus. Then, I wanna try Avast antivirus but I couldn't install it even I already uninstalled Sophos.

First of all, most anti-virus software will not find adware since it's considered to be annoying, but not malicious, so you're wasting time with both products. Secondly, Avast! comes with it's own adware, so you'll just make matters worse see Avast installs adware.

K Shaffer has given you the correct reference. Consider the use of TheSafeMac's Adware Removal Tool which will locate and remove most all currently known adware safely and efficiently.

You may have inadvertently installed adware. Eradicating it is simple. For an explanation or how this may have occurred, how to avoid it in the future, and for one possible solution read How to install adware.

Do not pursue an "anti-virus" solution for that problem. It won't help and is likely to cause unrelated problems. If you already installed an "anti-virus" product, uninstall it according to its instructions, and verify that it has been rendered completely and permanently inert.

"Avast" and "Sophos" are both worse than useless and neither should be installed.

Please post a screenshot that shows the popups. Be careful not to include any private information.

Start a reply to this message. Drag the image file into the editing window to upload it. You can also include text in the reply.