Prearm logging failed and no logs with the version 4.0.3

Hello . After upgrade of my arducopter from 4.0.1 to the last 4.0.3 , I receive the error message "Prearm: logging failed . Moreover , trying to access the logs with the button “Download Dataflash logs …” , the system tells me there are anything on the SD card, when in fact it contains old recorded logs.
I got around the problem by removing the option “Logging available” in the ARMING_CHECK to make a flight , but no logs has been recorded.

Returning to the 4.0.1 is okay , the message is gone and I can see my old logs.
I specify that I use a pixhawk 2.4.8.
But the problem is that without correcting this error of this new version, it’s not recommended to upgrade and fly safe without being able to analyze the incidents.
Thanks !!

Can you try 4.0.4-rc2? Can you post one of your .bin files?

Updating to 4.0.4 rc2, the problem has disappeared , but returning to the 4.0.3 too.
I don’t know what’s happened because my first update try has correctly finished . Maybe a bad reset of a component on the pixhawk (?). Sorry ,you can therefore close the incident and I will continue my tests with the 4.0.4 rc2.

As a side note, this is a good sign to format the sd-card or replace it

I had the the problem with 3 different Pixhawks and 4 differend SD cards that all worked before updating the firmware. This problem has nothing to do with the SD card and is still not solved with 4.0.4.

I could solve it be completey overwriting all data on the Pixhawk (full reset). To do so, i flashed arduplane and then newest arducopter again because I could not find the terminal anymore in newer MP versions. The tab is just gone although I set Layout to Advanced. Docs seems not up to date anymore. Really annoying when the view of MP is changed but not updated in the help or docs sites.

So it must be an old parameter transfered from older to newer ardupilot versions that causes the problem.

I updated my pixhawk cube orange to 4.0.4 and getting logging failed , have a new formatted 8GB SD card , same problem pre arm fail due to logging failed error
Any Help would be greatly appreciated


Try another SD card.

我重新格式化SD卡 FAT32 預設大小, 快速格式化.
ARMING_CHECK = 1 (重置為1 ,之前是亂碼 90xx 超出範圍的數值 )
目前上電後會提醒“ Prearm:記錄失敗 但能然可以解鎖.


I’m not sure if anyone is still monitoring this thread, but I have 4.1.7 on a new build with a Matek F405-WSE, and I get the Prearm: logging failed error as well. When I look at the contents of the card, in the Logs folder, there is a single bin file, but with length 0, and a LASTLOG.txt file. Both files are timestamped at the time of the attempt. It is a 32GB Sandisk uSD card that was previously used on a Pixhawk. There is another folder showing up that I don’t think I’ve seen before, STRG_BAK, and it has a bunch of files dated back at what appears to be an epoch date, 12/31/1979.

Reformat the card and try again.

Thanks, that did the trick.

I am also facing the same issue,
“Prearm:logging failed”
I am using copter 4.0.4, I tried formatting the SD card and also used different SD card, but noting seems working. I have to disable the logging check in prearm checks to fly. Added to that my log fiels sizes are too big (300MB to 400MB for 5min to 10min flight). :cry:. Need some help
Thank you