When iOS 8 became available for download yesterday, Sept. 17, many were rejoicing over its new features and functionality. However, one group may not be quite as enthralled with the new operating system for iPhones: health and fitness app entrepreneurs. According to PCWorld, a bug has infected the iOS 8 HealthKit, which is preventing third-party health and fitness apps from launching.

HealthKit itself is a new feature in iOS 8 that is designed to help developers’ apps communicate with native iOS health apps, pulling in data like heart rate or calories burned from devices and allowing apps to analyze the data. One of the examples used is a nutrition app that, when given permission, can transfer nutrition data to a fitness app to determine calories ingested vs. calories burned.

Published reports said that the bug in HealthKit was discovered when developers noticed their health and fitness apps were not being posted in the App Store. Apple then confirmed that it had put HealthKit on hold because its API (application programming interface, the code that allows HealthKit to integrate with other apps) wasn’t ready for use. The affected apps include Carrot Fit, WebMD and AskMD.

Of course, the HealthKit bug was discovered very shortly before the release of the iPhone 6, which is coming out Friday. Apple, meanwhile, doesn’t have an ETA on when the HealthKit bug in iOS 8 will be fixed, which is currently preventing health and fitness app entrepreneurs and developers from posting their work in the App Store and making money. The company stated that the bug should be fixed by the end of September, but that’s just an estimate.