Apple released its new iOS 10 mobile operating system Tuesday for iPhones and iPads, but a large number of users quickly complained the software rendered their expensive devices useless.

Eager smartphone and tablet owners downloaded the update only to discover that it “bricked” their devices, meaning the gadgets would shut down and refuse to start back up.

To use the devices again, users had to connect the iPhone or iPad to a laptop and complete a full restore of the operating system. In doing this, users risked losing photos, documents or other data that wasn’t backed up properly before downloading the update.

“Looks like I bricked both iPhone and iPad with iOS update,” Canadian tech entrepreneur Roustern Karimov posted on Twitter, joining a sizable group of angry Apple patrons grumbling about the update online.

After frustrated customers took to social media to complain about their inert devices, Apple quickly set up a support website to guide users through restoring the software. Several hours after iOS 10 was released, the company claimed that the issue was fixed.

“We experienced a brief issue with the software update process, affecting a small number of users during the first hour of availability,” Apple said in a statement. “The problem was quickly resolved and we apologize to those customers. Anyone who was affected should connect to iTunes to complete the update or contact AppleCare for help.”

Although iOS 10 has received good reviews from the tech press for its completely revamped messaging system, visual design tweaks and other features, the bricking issue will likely cause many users to wait before updating to the new system.

Apple is no stranger to similar bugs – earlier this year, an update to the operating system for its iPad Pro tablets was temporarily pulled back after reports it bricked those devices.