Trojan.Downloader.Kuluoz.U how do i remove it from my MacBook Air

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

About file quarantine in OS X

If you require anti-virus protection Thomas Reed recommends using Dr.Web Light from the App Store. It's free, and since it's from the App Store, it won't destabilize the system. If you prefer one of the better known commercial products, then Thomas recommends using Sophos.(Thank you to Thomas Reed for these recommendations.) If you already use Sophos, then be aware of this if you are using Mavericks: OS X Mavericks- Sophos Anti-Virus on-access scanner versions 8.0 - 9.1 may cause unexpected restarts

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.

That malware is Windows-only. It cannot infect your Mac.

It is possible that you have components of this malware sitting inertly on your Mac somehow, or it's possible that this is a false positive. Do not delete anything without further investigation!

What anti-virus program are you using?

For detailed information on how to properly delete these kinds of things from your hard drive, see: How to remove infected files.

(Fair disclosure: The Safe Mac is my site, and contains a Donate button, so I may receive compensation for providing links to The Safe Mac. Donations are not required.)

AVG on the Mac is worthless. When I tested it in January, it only detected 61% of the malware samples I threw at it. Uninstall it, using the appropriate item in the AVG Anti-virus menu within the AVG app.

From the sounds of it, you have installed some kind of adware... or, if all devices on your network are being affected, you may have a compromised network. See my Adware Removal Guide for help finding and fixing the problem in either case.

Regarding the removal of AVG, and whether to replace it with something else, see my Mac Malware Guide.

Also, be aware that malware that has infected your Android phone cannot attack your home network or any of those other devices.