A bug has delayed the introduction of several health and fitness applications designed to use Apple’s highly touted new HealthKit software, clouding Wednesday’s launch of the iOS 8 mobile operating system.
Apple acknowledged an unspecified glitch Wednesday, and said it is working to repair the problem by the end of the month.
“We discovered a bug that prevents us from making HealthKit apps available on iOS 8 today,” said Apple spokesperson Trudy Muller. “We’re working quickly to have the bug fixed in a software update and have HealthKit apps available by the end of the month.”
Several companies, including Lark, MyFitnessPal, Strava, Weight Watchers and Under Armour, had planned to introduce apps that would take advantage of Apple’s new operating system and its enhanced sensors in the next-generation iPhone 6 and iPhone 6 Plus smartphones.
Early Wednesday morning, a Lark spokesperson contacted Re/code, asking that the company be omitted from coverage of the iOS operating system, saying, “Apple just notified us that Lark will not be available today.”
A Lark spokesperson did not respond to requests for further comment.
Strava issued a statement, saying the latest version of its app would not be available “due to issues beyond our control.”
“We’re working on a new version of the app that will still incorporate some of iOS 8’s new features, like the Notification Center widget, and will contain other features designed specifically for runners and cyclists,” a Strava spokesperson said in a statement. “We hope to have it available in the App Store as soon as possible.”
One app maker received a single-sentence email from Apple, notifying it to hold all communications because of a bug. Apple did not provide further details.
Another developer that was planning on rolling out a new version of an application that capitalized on both the new operating system and HealthKit was scrambling to tweak the product so that it would work on the new iPhone 6 and iPhone 6 Plus, which are due out Friday.
HealthKit, which was unveiled in June at Apple’s Worldwide Developers Conference in San Francisco, provides a central repository for information about a person’s exercise regimen, sleep habits, diet and even medical information.
Health-care providers, including the Mayo Clinic and the Cleveland Clinic, were exploring ways to properly harness such data in treating patients with chronic medical conditions such as high blood pressure and diabetes.
Apple Chief Executive Tim Cook highlighted the health and fitness capabilities of the iPhone 6 and iPhone 6 Plus phones at their unveiling, saying the software holds the promise of helping people become healthier and more active.
“This is a very important area for me and a very important area for Apple,” Cook said during the presentation.
This article originally appeared on Recode.net.