Apple is finally acknowledging there's a big problem with some MacBook screens

Apple is finally acknowledging a problem plaguing thousands of MacBook and MacBook Pro customers, MacRumors reports, and has begun replacing the screens of affected devices for free.

The issue is popularly known as "Staingate," and involves the anti-reflective coating on some laptop screens failing. The result is ugly cosmetic "stains" across the screen.

It's difficult to quantify exactly how many people have been affected by the issue, but it appears to be in the thousands. More than 4,000 people have joined a Facebook group for Apple customers who have experienced Staingate, and around 4,700 have signed a petition to Apple launched early in 2015 calling for a free fix.

The issue appears to affect devices sold from June 2012 onwards, and seems to be caused (at least in some cases) by cleaning.

Citing multiple sources, Apple blog MacRumors says that the Cupertino company is now addressing the issue. It will replace devices that have been affected free-of-charge that have been bought within the last three years via a "Quality Program" - an acknowledgement of a common fault.

Multiple customers are also reporting on the Staingate Facebook page that Apple is replacing affected devices free-of-charge.

Business Insider has reached out to Apple for comment and will update this story when it responds.