I recently was asked by a user (a person with no large technological background) a basic question: how he can disable an antivirus. When I asked why would he want to disable it, the person explained that this was requested when installing an application.
Further questions made it appear that it is a malware disguised as an ordinary freeware product. From what I've seen, this is not the only malware which invites the user to disable an antivirus or to ignore warnings which may be shown by the antivirus.
Still, I remember a few cases where legit applications required to disable an antivirus during installation. I don't remember which ones, but there were well-known products from large companies (Adobe CS, maybe?)
Why would they, given that this gives a very bad habit to the users?
What could be a problem for the legitimate application to be installed in a context where an antivirus is on?