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Microsoft has decided to crack down on the growing number of free programs that claim to scan computers for errors and then pressure worried PC users into upgrading to paid versions for a cure.

Starting March 1, Windows Defender Antivirus and other Microsoft security products will classify programs that display bullying messages as unwanted software, and they will then be deleted, Microsoft says.

"In the future, programs that display coercive messaging will be classified as unwanted software, detected, and removed," Barak Shein of Windows Defender Security Research said.

Some free programs promise a check-up but then "use alarming, coercive messages to scare customers into buying a premium version of the same program", he wrote. This approach can be a problem when it pushes customers into making unnecessary purchases.

To protect customers, Microsoft is updating its evaluation criteria to make it clear that programs must not use the type of messaging that pressurizes customers into purchases or performing other actions.

Free PDF download: System update policy

These evaluation criteria are used to determine what programs are identified as malware and unwanted software.

Microsoft has already taken steps to tackle programs that display misleading, exaggerated, or threatening messages about a system's health.

In February 2016, it ordered that programs that claim to clean up systems and optimize performance must provide customers with detailed information about what purportedly needs to be fixed.

This move aims to protect PC users from programs that present aggregate "error" results with no specific details, giving customers no way of assessing and validating the so-called errors.

Microsoft defines software that coerces users as products that report errors in an exaggerated or alarming manner and requires the user to pay for fixing the errors or issues, or by performing other actions such as taking a survey, downloading a file or signing up for a newsletter.

The software may also imply that no other actions will correct the reported errors or issues, or require the user to act within a limited period of time to get the purported issue resolved.

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