Apple prevented several healthtech startups from launching or updating their iOS 8 apps last night after it found a bug in its new HealthKit platform.

Apple's HealthKit feature enables health and fitness apps to share people’s data between themselves, as well as with the new Health app, which is being automatically rolled out with iOS 8.

A number of apps, including Sleepio, a CBT app built by UK startup Big Health, were due to launch HealthKit-compatible apps or updates as iOS 8 rolled out yesterday but Apple’s software issue means the new apps have been put on hold. 

In a statement, Apple said it had discovered a bug in the system, preventing the release of compatible apps as scheduled for Wednesday alongside the launch of iOS 8.

"We're working quickly to have the bug fixed in a software update and have HealthKit apps available by the end of the month," a spokeswoman said via email.

It's believed that a number of HealthKit-integrated apps will revert to previous versions in coming days in order to avoid losing potential customers. 

Indeed, the app development team behind Sleepio are understood to have worked all through last night in order to get a non-HealthKit-compatible version of their app in the App Store this morning.

Other healthtech apps that were prevented from launching their HealthKit-integrated apps include MyFitnessPal, WebMD and Carrot Fit.

A developer at Carrot Fit told told Cult of Mac that Apple called him to inform him of the problems.  “The rep couldn’t clarify what was wrong, though users of the app who had already downloaded the update were able to use the HealthKit features without any issue.”

The HealthKit platform is set to be one of the key selling points for the much-anticipated Apple Watch. However, if the bug is fixed by the end of September, as Apple claims it will be, then it's unlikely to have an impact on the wearable device's launch in early 2015.