The quality of Apple’s iOS is being called into question, this time because of a bug that is crashing iPhones when the user watches a certain video on them. Some Reddit users shared details about the new bug in a post yesterday.

This 5-Second Video Is Crashing iPhones: How To Recover If You Watched It

Crashing iPhones thanks to an MP4

An MP4 video causes this latest bug; all a user needs to do to have their iPhone crash is watch it. Having tested this bug on multiple iPhones, we can tell you that watching it will crash iPhones running on iOS 5 and above. In fact, it will even crash iPhones running on the iOS 10.2 beta. However, every one of the crashing iPhones was quickly brought back into a working state.

How to fix the problem

As a precaution, we’re not going to publish a link to the video. However, should you watch it, here’s how to recover your device.

The solution is a simple one; all you have to do is a hard reset. So on devices older than the iPhone 7 and 7 Plus, that means long-pressing the power button and the home buttons at the same time. However, if you’re an owner of the latest-generation iPhone, you can’t solve this problem like this.

Apple removed the mechanical home button in the iPhone 7, so to recover a crashed iPhone 7, you need to long-press the power button and the downwards volume button at the same time.

What causes the crash?

As we mentioned earlier, we’re not going to share the video or file that’s crashing iPhones. But  if someone sends you a message via iMessage asking you to watch a file named IMG_0942.mp4, DO NOT WATCH IT. This is the file name of the video we’ve been talking about which has resulted in crashing iPhones, and apparently, crashing iPads too.

The crash happens when the video is viewed via the Safari browser. It takes between 15 and 30 seconds for a user to realize that something is wrong with their device. No one knows why this happens, and even Apple has yet to comment on the problem officially.

The above video by Everything Apple Pro talks about the effects seen by iOS users who have experienced crashing iPhones due to this bug, but it fails to shed any light on why the bug exists and how it is causing the crashes. There’s a chance that this is just a prank gone wrong. According to Anthony Vanover, a commenter on 9to5Mac, the reason could be as follows:

“I inspected the video file in 010 Editor. There’s an extra structure at the end of the file with no defined size. In fact, the entire structure is just “0D 0A”. That is, it’s a carriage return and line feed, but a video player may try to interpret it as the size of the current structure which, in this case, is 3338 (unsigned integer) which is larger than the end of the file itself.

“I suspect this structure was put there by accident and that there’s a bug in the Safari web browser.”

Other reports of crashing iPhones

This isn’t the only time crashing iPhones and iPads have been reported due to a bug. Earlier this year, another Safari bug wreaked havoc, causing Apple’s devices to crash. In 2015, there was a bug that caused crashing iPhones, Apple Watches, iPads and Macs. So while Apple’s system may be tighter than Android when it comes to malware and viruses, obviously it can fall victim to stray code now and then.

We don’t know when Apple will address this. However, should enough people report the problem, we’ll probably hear something soon. In the meantime, if you receive a link or file you weren’t expecting, be extra vigilant. The best advice we can give is if you’re not expecting something, don’t click or open it.