A pinned post at the top of the official Charge 5 forum for the device's most recent firmware (version 194.91) now has over 400 comments, with many owners complaining that their updated tracker now loses charge overnight or is even "completely unresponsive".
We've asked Google, which has owned Fitbit since 2019, for an up-to-date response on the issues and what might be causing them. So far, Google has only issued a statement to the BBC denying that the Charge 5's firmware update is causing the problems.
In that statement, a Google spokesperson said: "We're still investigating this issue, but can confirm it is not due to the recent firmware update." The tech giant added that "users should continue to update their devices to the latest firmware and contact Fitbit Customer service at help.fitbit.com if they encounter any issues."
But this is unlikely to quash the growing frustration on Fitbit forums, where some users are understandably regretting updating their Charge 5 and have even (in the case of forum user 'Gevans1388') been offered a 35% discount off a new Fitbit when they reported the issues.
Some users have suggested restarting the Fitbit or doing a factory reset, which involves going to Settings > Device Info > Clear User Data, then pressing the 'Hold 3 Sec' button for three seconds and releasing. But this isn't something Google or Fitbit has recommended and it isn't an option if your device is unresponsive.
We'll update this article as soon as we hear back from Fitbit.
Another Fitbit furore
These Charge 5 issues are the latest in a long line of controversies and calamities that have taken place since Google acquired Fitbit in 2019. Most recently, Fitbit has had to extend a fig leaf to furious fans in the form of several highly-requested app fixes.
This followed some widely-reported issues in 2022 about the Charge disconnecting from Bluetooth, which wrecked many users' sleep-tracking graphs. Also, in October 2022, Fitbit ended the ability to download music files onto smartwatches like the Versa 3 and original Fitbit Sense. This led us to conclude that Google's slow destruction of Fitbit was everything that's wrong with modern tech.
It should be stated that not all Charge 5 owners are having issues following the 194.91 software update. For example, forum user 'bbunge' said they updated "without a hitch" and that battery life was actually "better by a couple of days" with the new firmware. Google's current stance is also that the firmware isn't causing any of the reported issues.
Yet the overwhelming consensus from the hundreds of Fitbit forum comments is that various issues, from battery drain to a completely unresponsive device, have arisen following that most recent firmware update. And while last year's app redesign was more of an inconvenience, these seemingly software-driven problems are understandably causing more anger.
We'll be following up again with Google and Fitbit soon and will update this article as soon as we hear any further advice about what you should do if you've been hit by any of these Charge 5 issues.
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Mark is TechRadar's Senior news editor. Having worked in tech journalism for a ludicrous 17 years, Mark is now attempting to break the world record for the number of camera bags hoarded by one person. He was previously Cameras Editor at both TechRadar and Trusted Reviews, Acting editor on Stuff.tv, as well as Features editor and Reviews editor on Stuff magazine. As a freelancer, he's contributed to titles including The Sunday Times, FourFourTwo and Arena. And in a former life, he also won The Daily Telegraph's Young Sportswriter of the Year. But that was before he discovered the strange joys of getting up at 4am for a photo shoot in London's Square Mile.