Q: Virus on Safari

Welcome to Apple Support Communities. We're all users here.

I won't guarantee that it will solve your problem, but Firefox Version 20 (I'm running OS X 10.6.8) does have Extensions.

Firefox, Tools, Add-ons Manager, and choose the Extensions tab

The Adblock Plus extension (free) might also help.

Thanks very much. (you'll have to excuse my ignorance, i'm fairly rubbish when it comes to computers).  Unfortunatly it doesnt solve the problem as my Extensions box is blank. I looked all around there and still cant find the thing suggested to get rid of the malware.

See:

Eliminating browser redirects and advertisements

Thanks, a very good and clear article, however I followed the steps and it did not solve the problem.  Its only a browser specficic problem (it only happens on Firefox, not Safari), so will it cause any further problems if I just forget about it and switch to using Safari instead?

In Firefox, did you check BOTH theExtensions list and the Plugins list? (See kostby's screenshot above.) if not, you need to do that. Browser-specific behavior is likely to be some kind of browser-specific extension or plugin.

I did yes but it was only a Facebook one in the plugins which seemed out out place and also cropped up when I followed the instructions in that article., removed this and the problem was still there. Randomly enough however when I just opened firefox again it seems to have stopped so thanks for all your help.

Hello, I have the same problem but I'm not sure if I am at the right place or not.

As you can see form the image inserted, I can't find the M-Codec. I use google as a search engine.

Please help, I would really appreciate it.

Like most annoyances "Codec-M" or "M-Codec" has been a moving target, but you should definitely uninstall both the "Spigot" and "Conduit" extensions that appear in your screenshot. Those are intrusive adware products that most people find annoying.

Because adware is constantly changing, you may not find an answered question containing timely information by searching old discussions such as this one.

Merely removing those extensions may not suffice. You may need more assistance, and if simply removing them through Safari's Preferences does not solve the problems you're describing, please post a new question such as this: How can I remove Spigot and Conduit from Safari?

Post it in the Safari forum.

I use google as a search engine.

I recommend you don't. Google is probably more responsible for users downloading Mac malware by following Google's advertisements than through other source. Google doesn't care that their revenue is derived from garbage product advertisements, and they certainly won't care if you mess up your Mac by installing garbage products.

As you can see form the image inserted, I can't find the M-Codec.

You're responding to a post from 2012, and things have changed a lot since then. Adware was rare back then, but not anymore.

Your screenshot shows that you have the Spigot and Conduit adware installed. You may have other adware installed as well, as not all adware installs browser extensions. See my Adware Removal Guide for help finding and removing it.

(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.)

Thank you so much for this adware removal link - I was having the same problems and it's completely fixed it