Olathe, Kansas, April 15, 2026, 13:34 CDT
Fresh complaints about Garmin smartwatch software problems flared again this week, with some Forerunner owners saying months-old sensor bugs remain unresolved and iPhone users reporting persistent syncing failures. The latest reports pull together trouble with heart-rate, altitude and sleep data, the functions many runners use to guide daily training.
That matters because Garmin sells premium sports watches on the accuracy of their training metrics, not just on battery life or phone alerts. When heart-rate or altitude readings go bad, they can skew workout intensity, recovery advice and VO2 max, a common estimate of aerobic fitness; when the phone link fails, workouts and notifications may not sync at all.
Garmin’s own support pages show software version 27.09 began rolling out on Jan. 16 with promised fixes for scrolling lag, swim crashes and certain touchscreen issues. Yet Garmin forum threads tied to the same software have kept piling up across Forerunner models, with complaints ranging from missing sleep data and broken wrist heart-rate readings to battery drain and erratic elevation numbers.
One Forerunner 255 post from late March said altitude values on version 27.09 swung from 4,000 to 8,000 below normal even after GPS calibration. A separate 955 thread said the watch stopped tracking sleep and only recorded heart rate sporadically overnight after the same update.
Garmin did push at least one follow-up fix. Its Forerunner 165 support page shows version 27.10 was released on Feb. 4 to address data dropouts on some devices, and one 265 owner later wrote that step counts, heart rate, Body Battery, Garmin’s energy score, and related metrics appeared fixed after 27.10; other posts on the 165 and 955 lines said sleep tracking and heart-rate problems still remained.
A separate fault line has opened on Apple’s iPhone. Garmin forum threads from February and March said some watches would show up as connected in Bluetooth settings but not in Garmin Connect, leaving users unable to sync data or receive notifications, and a newer thread said the problem was still present on iOS 26.4 and Garmin Connect 5.23.
Garmin support said in February that Garmin Connect 5.21.3 should address the pairing issue and pointed users to extended troubleshooting, but later replies said the failures continued. Notebookcheck reported on Wednesday that some Garmin wearables paired with iPhones were still close to unusable for affected owners, though wired syncing could still move workout data.
Complaints are not limited to the Forerunner line. On Garmin’s Fenix 8 forum, threads updated within the past week challenged sleep-tracking accuracy, with one April 6 post linking to video evidence and another long-running discussion arguing Garmin’s sleep tracking still needs work in 2026.
The software friction lands at an awkward time for Garmin. In its Feb. 18 earnings materials, CEO Cliff Pemble said 2025 was “another year of remarkable growth and achievement” and later told investors he expected “another year of strong performance for fitness,” while the company forecast 2026 revenue of $7.9 billion after fitness-segment sales rose 42% in the fourth quarter. Garmin
That makes reliability more than a customer-service headache. Garmin competes with Apple and Samsung in premium wearables, while smaller sports-watch rival Coros is being pitched this week as a cheaper option for runners, and Morningstar analyst Eric Compton wrote in February that Garmin is taking share in fitness and outdoor wearables.
But the scope of the problem is still hard to pin down. Some users in the same discussions said their watches were unaffected or that re-pairing steps, older app versions or newer firmware restored normal behavior, which suggests the failures may be model-specific or tied to particular iPhone, app and software combinations rather than a single bug hitting every Garmin watch.
