Hi everyone, I'm building a health-focused iOS and watchOS app that uses WatchConnectivity to sync real-time heart rate and core body temperature data from iPhone to Apple Watch. While the HealthKit integration works correctly on the iPhone side, I'm facing persistent issues with WatchConnectivity — the data either doesn't arrive on the Watch, or session(_:didReceiveMessage:) never gets triggered. Here's the setup: On iPhone: Using WCSession.default.sendMessage(_:replyHandler:errorHandler:) to send real-time values every few seconds. On Apple Watch: Implemented WCSessionDelegate, and session(_:didReceiveMessage:) is supposed to update the UI. Both apps have WCSession.isSupported() checks, activate the session, and assign delegates correctly. The session state shows isPaired = true and isWatchAppInstalled = true. Bluetooth and Wi-Fi are on, both devices are unlocked and nearby. Despite all this, the Watch never receives messages in real-time. Sometimes, data comes through in bulk much later or not at all. I've double-checked Info.plist configurations and made sure background modes include "Uses Bluetooth LE accessories" and "Background fetch" where appropriate. I would really appreciate guidance on: Best practices for reliable, low-latency message delivery with WatchConnectivity. Debugging steps or sample code to validate message transmission and reception. Any pitfalls related to UI updates from the delegate method. Happy to share further details. Thanks in advance!

Hi everyone, I’m a student developer currently building a watchOS app that uses HealthKit and HKWorkoutSession to estimate core body temperature from real-time heart rate data. The app runs well in the simulator, but testing on a physical Apple Watch has been extremely difficult. Each time I try to run the app from Xcode (Version 16.3), the build gets stuck on: “Copying shared cache symbols from MyWatchName (0% completed)” Sometimes it just stops stating connection failure. However, more often no errors are shown, but the sync never finishes. I’ve tried the following without success: Restarting the watch, iPhone, and Xcode Switching networks (Wi-Fi and hotspot) USB wired pairing Resetting developer settings and trust prompts Deleting derived data Rebuilding the project This is especially limiting for a real-time health tracking app where I need to monitor HKLiveWorkoutBuilder data while the screen sleeps — which can’t be tested effectively in the simulator.