My FitBit One decided to take a nap on February 2nd, 2017. Sorry you have to deal with a "non-syncing" unit. This is not the first occurrence for me as the my unit quit syncing on the twenty-third of December 2016. I paid close attention to the specifics regarding this last sync failure. Microsoft had just installed either a system upgrade or security upgrade approximately thirty minutes before I attempted to sync my FitBit One.
I have contacted FitBit in the past but my experience with their ability to resolve issues, has been less than encouraging. I have a Microsoft Windows 7 Profession Edition operating system. According to FitBit, they no longer support this system to function with their current product line(s) or system upgrades?
I have owned my FitBit One for fourteen months. My opinion is that FitBit has become like so many operations, as they got bigger, their ability to service customers has taken a nosedive and people like me will eventually seek out alternative products with greater levels of reliability.
Suggestion, have you tried syncing your FitBit One to a different computer? If a second computer will not successfully let your FitBit One communicate with your Dongle, either the Dongle or your FitBit One is defective or possibly, antivirus software is blocking your Dongle from communicating with the computer.
