Apple is releasing a security update that removes fake security software that has caught out thousands of Mac users.
Once installed, the fake MacDefender, MacProtector and MacSecurity programs pretend to scan a machine and then ask for cash to fix non-existent problems.
The gang behind the programs used search sites to help catch people out.
The clean-up plan starts as the creators of the fake programs release a version harder to avoid.
In a message posted to its support forums, Apple has warned users about the fake security software, also known as scareware.
It said a phishing scam had targeted Mac users by redirecting them to sites that warned them that their machine was infected with viruses.
Apple said it would release an OS X update soon to find and remove MacDefender and its variants. The message also gave advice about how to remove the software if they had already fallen victim.
MacDefender and its variants are thought to have caught some people out because the default security settings on the Safari browser allow it to download and queue itself for installation.
Those who install it can end up paying more than $70 (£43) to remove the non-existent viruses the scareware claims to have found.
As Apple was releasing its fix for Mac Defender, the gang behind it had started distributing a new version.
Like older versions, the new one - called Mac Guard - is being spread by tying it to popular phrases typed into search engines.
Mac Guard also gets round one of the factors that limited the spread of Mac Defender as it no longer needs a user's permission to be installed.
Security firm Intego issued a warning about the variant and said those who use the Safari browser should disable a setting that lets "safe" files be installed automatically.