A San Francisco teenager recently found themselves on the receiving end of a massive $2,021.07 phone bill — courtesy of iOS 9’s Wi-Fi Assist feature, which automatically switches phones to use cellular service when the owner is in an area with a weak Wi-Fi signal.
Teen Ashton Finegold made the unpleasant discovery that his bedroom was such a place, which meant that while he thought he was connected to his home Wi-Fi setup, his iPhone actually clocked up 144,000 MB of cellular data.
“I thought my dad was going to kill me,” he told CBS News.
This isn’t the first time we’ve heard reports about how Wi-Fi Assist can accidentally burn through mobile data plans, which has prompted Apple to release a support document detailing how and when Wi-Fi Assist should work.
While Wi-Fi Assist is switched on by default, Apple gives three caveats to help people understand when their data can be used by the feature:
- Wi-Fi Assist will not automatically switch to cellular if you’re data roaming.
- Wi-Fi Assist only works when you have apps running in the foreground and doesn’t activate with background downloading of content.
- Wi-Fi Assist doesn’t activate with some third-party apps that stream audio or video, or download attachments, like an email app, as they might use large amounts of data.
Although the best option is to have Wi-Fi Assist running on an unlimited data plan, if you are on a limited monthly data plan it is possible to turn off the feature by following these simple steps. You can also download iOS apps like Download Meter which help you keep track of your monthly data usage to avoid going over your limit.