What just happened? Microsoft says it will be offering free repairs on Surface Laptop 3 devices that experience a strange phenomenon in which the screen cracks for no apparent reason. If your machine is affected, you shouldn't wait too long before sending it away: the free offer is only applicable while the laptop is under warranty.

A few months ago, some Surface Laptop 3 owners found that cracks were appearing spontaneously in the displays. Microsoft said it was investigating the problem, and has now revealed that a hard, foreign particle was the cause. Whether this refers to something that made its way into the screen externally, or is part of the device itself, is unclear.

"(We) have determined that, in a very small percentage of cases, a hard foreign particle may cause a hairline fracture in the glass that may seem to appear unexpectedly or without visible cause," wrote officials.

Microsoft says it will only repair the affected Surface Laptops, both 13-inch and 15-inch versions, while they're under warranty. They went on sale last October, so that shouldn't be a problem if you don't wait too long. And don't try to get a free repair for damages you've caused, Microsoft will know. Additionally, those that previously paid Microsoft to repair damage caused by this issue can apply for a reimbursement.

ZDNet notes that Surface Laptop 3 devices with aluminum cases, as opposed to those with the Alcantara fabric, are more prone to the cracking.

Some Redditors (via TechRadar) speculate that the issue may be a result of the laptops' lack of rubber seal around the display. Whatever caused it, we should assume Microsoft has now addressed the problem in new models.

This isn't the only incident of unexplained cracks appearing in devices. Some owners of Samsung's Galaxy S20 Ultra have found its rear camera is inexplicably shattering.