Q: my macbook air has a pop up virus

The Safe Mac » Adware Removal Guide

Helpful Links Regarding Malware Protection

An excellent link to read is Tom Reed's Mac Malware Guide.

Also, visit The XLab FAQs and read Detecting and avoiding malware and spyware.

See these Apple articles:

  Mac OS X Snow Leopard and malware detection

  OS X Lion- Protect your Mac from malware

  OS X Mountain Lion- Protect your Mac from malware

  OS X Mavericks- Protect your Mac from malware

  About file quarantine in OS X

If you require anti-virus protection Thomas Reed recommends using ClamXAV. (Thank you to Thomas Reed for this recommendation.)

From user Joe Bailey comes this equally useful advice:

The facts are:

     1. There is no anti-malware software that can detect 100% of the malware out there.

     2. There is no anti-malware that can detect anything targeting the Mac because there

          is no Mac malware in the wild, and therefore, no "signatures" to detect.

     3. The very best way to prevent the most attacks is for you as the user to be aware that

          the most successful malware attacks rely on very sophisticated social engineering

          techniques preying on human avarice, ****, and fear.

     4. Internet popups saying the FBI, NSA, Microsoft, your ISP has detected malware on

         your computer is intended to entice you to install their malware thinking it is a

         protection against malware.

     5. Some of the anti-malware products on the market are worse than the malware

         from which they purport to protect you.

     6. Be cautious where you go on the internet.

     7. Only download anything from sites you know are safe.

     8. Avoid links you receive in email, always be suspicious even if you get something

         you think is from a friend, but you were not expecting.

     9. If there is any question in your mind, then assume it is malware.