Logging Error after downgrading from v3.7.0-dev

Hi Guys,

I was running ArduCopter v3.7.0-dev until now for the FrSky Telemetry hack but just recently noticed that it’s not a very safe firmware to run. I then flashed ArduCopter v3.6.9-stable. The copter flies fine but there’s no way to get a working log.


  1. Error when trying to review log: “Log Browse will not function correctly without FMT messages in your log. These appear to be missing from your log.”
  2. Sometimes when downloading the logs it marks them as 0KB empty, but when reading the logs directly from SD card they are 1-8MB.
  3. Sometimes when connecting via Mission Planner / USB it gets stuck reading params like STAT_RUNTIME, when hitting ‘cancel’ it still connects to drone.


  1. Formatted current SD card on FAT32, deleted all contents, started fresh
  2. Switched to a new FAT32 formatted SD card
  3. Tested logging while disarmed - this works fine
  4. Tested logging while quick hover test: Log review error -> “Log browse will not func…”
  5. Tested changing log_bitmask parm from 173821 to 830(default).
  6. Tested another standalone Pixhawk, logging on ‘disarmed’ and it logged well.
  7. Tested resetting params to default, loaded old params in and made sure they were all good.
  8. Tested with Log_Reply = 0 (originally 1)
  9. Tested with Log_File_bufsize = 8 (originally 40)

Problem still persists, all of my logs in flight are corrupted. It doesn’t matter which SD card I use and none are clones. What could it be? Thanks!

It turns out that formatting the SD card on my Macbook running Windows bootcamp was the culprit.

Solution: Format SD card on native windows PC.