There are still Trojans out there

[Xairbusdriver]

Recent Trojan installs things that may cause unexpected pop-up adds/windows, unwanted web pages, etc. It has to be downloaded, and it then has to be installed with the user's help (you can usually see who that user is by looking in a mirror 'site', like the one in most bathrooms). Of course, you were not told that the trojan would installed, along with whatever 'must-have' app you thought you were installing.

It is fairly easy to remove, either manually or by using an AdwareMedic. Trojans seldom come with Un-installers... Manual removal instructions are at <MacIssues> including a link to AdwareMedic.

[gunug]

The last MAC malware I "fixed" was one of those "blackmail" things where it hijacked Safari.  I finally just used ONYX to zero out all the Safari "customization" and return it to it's original settings.  I'm not saying this
might not have been overkill but it worked! BTW The instructions to try to "do it yourself" were some that I had tried but they didn't work!