Q Although my iMac is now clear of MacKeeper, today I have had a series of popup adverts for it, when browsing with Chrome. How can I stop those?

A This is nothing local on your Mac, merely an ad being delivered by a remote server. You can take action to block the popup, by changing your browser’s settings, blacklisting the site shown as generating the popup in your firewall or in the Parental Controls pane, or installing a browser extension for this purpose. However this is a cat-and-mouse game, in which you will discover that advertisers then use different sites to circumvent your blocking or blacklisting. You may find it easier to just close the window and move on.

Comments This will change with the arrival of Safari 9, in OS X 10.11 El Capitan, as that will support content-blockers in general, including ad-blockers.

You should also be very circumspect about visiting sites which generate MacKeeper popups: similar devices have been used to serve Trojans at the unsuspecting. Any site which advertises MacKeeper in this way could be malicious.

Updated from the original, which was first published in MacUser volume 30 issue 7, 2014.