Garmin Forerunner update triggers tracking issues across multiple models
Firmware version 27.09 for Garmin’s Forerunner lineup started rolling out in mid January. Since then, users across several models have reported serious issues with step tracking, sleep detection, heart rate accuracy and overall performance.
Early complaints reported on Garmin Forums focused on the Forerunner 165, but it has since become clear that this is not an isolated case. Reports now include the Forerunner 265 and 965, with some users of older x55 models also flagging unusual behaviour. The severity varies, but the pattern points to a broader software problem rather than a single device fault.
Forerunner 165 remains the worst affected
A large number of users say their watch effectively stopped functioning as a fitness tracker after updating. Step counts freeze at zero, sleep tracking disappears entirely, and heart rate readings become either flatlined or wildly inaccurate. The Forerunner 165 appears to be bearing the brunt of the damage.
During runs, heart rate often sticks in the low 70s regardless of effort, then suddenly jumps before dropping back again. GPS performance is also impacted for some, with delayed starts, unstable pacing and repeated on track and off track alerts. Interface lag is another common theme, with start and stop buttons taking several seconds to respond.
Battery life has also taken a hit. Users who previously charged once a week now report barely getting two days. Factory resets, restarts and resyncing through Garmin Express rarely resolve the issue.
Other Forerunner models show similar symptoms
The Forerunner 265 and 965 are not immune. Several owners report degraded wrist based heart rate performance since installing 27.09, including slow response to intensity changes and odd cadence locking during runs. Others mention sluggish menus and delayed interactions during activities.
That said, these models appear less consistently affected. Some users report no issues at all on the same firmware, which suggests the bug does not trigger reliably across all hardware or usage patterns. Even so, the fact that core sensors are misbehaving on premium models has raised eyebrows.
Garmin response remains limited
What makes this update particularly frustrating is that it breaks fundamentals. Step count, heart rate and sleep are baseline features. When they fail, everything built on top of them becomes unreliable. Training load, recovery metrics and VO2 estimates lose context. Even casual users are left wondering whether the watch can be trusted at all.
There is also growing criticism of Garmin’s update process. Users are once again calling for firmware downgrade support, even if it requires a manual or desktop based approach. Right now, anyone affected is stuck waiting for a fix with no official way back to a working version.
Garmin moderators have acknowledged the issue in forum threads and have contacted some users directly to request diagnostic logs. That confirms the company is aware of the problem. What’s missing is a public status update or a clear timeline for a fix.
For now, if your watch is still behaving normally and you have not installed version 27.09, holding off may be the safest option. I’ve already installed it on my 955 and have not experience any issues. But for those already affected, the only real choice is to wait and hope a corrective update arrives soon.
Sources: Reddit, Garmin Forum via NotebookCheck
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