Malware Bytes

DiKat wrote:

My iMac has a message saying that a new version of Malware bytes is available for download is this something I should download ?

You most certainly should not download and install something—no matter what it is—simply because some random message appears saying you should. That is a common scam artist tactic that leads to installing malicious software. If you want to install or update something on your Mac, navigate on your own to the App Store or the developer's website—never by clicking a link appearing in a popup window or message.

Read Beware bogus Adobe Flash "installers" for a description of how that tactic leverages the ubiquity of another popular product. As explained in it, Flash Player is already outdated and the scam artists are certain to move on to something else.

The fact you don't appear to be certain it's already installed is reason enough to question its appearance.

Malwarebytes is general pretty benign. It is often recommended in the community as a tool to identify and help remove adware and malware. It can, but does not have to, actively run as background protection for your Mac.

If you rarely or never use it then you can safely ignore that.

It is certainly not something you need, or that is part of the OS. It is a third party app that you can use, but it sounds as if you have never intentionally installed it. I would just delete it in that case.

Great! Mystery solved.