I have a virus

Please post the exact, complete text of the message, or a screenshot.

What told you there was a virus?

Note that if some random website tells you that it has detected that you have a virus, that is almost certainly a scam to try to get you to install malware. Most likely, at this point in time, it would be Windows malware and not a threat to your Mac, but still, it's best to be wary.

If Facebook itself told you that you're infected, and wouldn't let you log in, that's likely to be caused by your Facebook account being hacked and used for Facebook spam. You will need to contact Facebook to re-gain access. No malware is involved.

If neither of these things are correct, please clarify.

It is most likely the advert for some worthless software rather then a virus.

It is not possible for anything on the web to check out your Mac for virus without you giving it permission to install itself and run on your Mac.

I concur with Linc, please post the complete text.

Allan

Det verkar tyvärr som att din dator är infekterad av ett virus.

Men du behöver inte oroa dig. Vi hjälper dig att hitta och ta bort eventuella skadliga filer med en gång.

When I log in to to Facebook from my Macbook Air I get the message above ("my account has been blocked due to virus in my computer"). However, I call still access my Facebook account via my Ipad. Strange isn't it?

Do you believ that my Macbook Air is infected by a virus?

NEJ!

Det er falsk reklame fra nogle der vil stjæle din identitet.

Der findes ingen viruser der kan angribe OS X.

There are many forms of ‘Malware’ that can affect a computer system, of which ‘a virus’ is but one type, ‘trojans’ another. Using the strict definition of a computer virus, no viruses that can attack OS X have so far been detected 'in the wild', i.e. in anything other than laboratory conditions. The same is not true of other forms of malware, such as Trojans. Whilst it is a fairly safe bet that your Mac will NOT be infected by a virus, it may have other security-related problem, but more likely a technical problem unrelated to any malware threat.

You may find this User Tip on Viruses, Trojan Detection and Removal, as well as general Internet Security and Privacy, useful: The User Tip seeks to offer guidance on the main security threats and how to avoid them.

https://discussions.apple.com/docs/DOC-2435

More useful information can also be found here:

www.thesafemac.com/mmg

Thank you Klaus!

But why is it possible to enter my Facebook account via my ipad without any comment about viruses (while I am blocked when I try to enter Facebook via my Macbook Air?). It gives me the impression that there is something in my Macbook that Facebook identifies as potentially dangereous.