Apple Users Report Glitches With iOS 10 Downloads

Apple Inc. ran into trouble with the release of iOS 10 just hours after making the new version of its mobile operating system available for download, as users took to Twitter to report troubles installing the software.

People installing iOS 10 posted screenshots of their devices, saying the hardware was rendered useless -- or "bricked" -- after installing the latest version of Apple's operating system.

In a statement, Apple said it had resolved the problem.

"We experienced a brief issue with the software update process, affecting a small number of users during the first hour of availability, " Apple said. "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."

The extent of the problems wasn't immediately clear. Some users said the troubles came when they tried downloading iOS wirelessly, or "over the air," instead of through a wired connection to a computer.

The release of iOS 10 comes days before the new iPhone 7 will be available to buyers. The new version of the OS represents a significant overhaul, including many features such as a more robust messaging system.

It isn't the first time Apple has run into trouble distributing iOS. Two years ago, Apple halted downloads of iOS 8 after customers said the initial update disrupted their ability to make phone calls and use the TouchID fingerprint sensor. The company has also worked over the years to slim down the size of the iOS download after users complained about having to delete apps to make room for the new software.

Write to Brian R. Fitzgerald at brian-r.fitzgerald@wsj.com