UM46k/Pro - CFast card file system corruption bug

I guess at some point everyone here got the dreaded Windows message after inserting a CFast card into the reader, that there has an error occurred and Windows has to repair the file system of the card.
It always seemed to happen out of nowhere and was not really reproducible. Until now

My configuration:
UM46k @ FW4.9 / CFast card Angelbird AV Pro 256 GB - both slots populated

First I did some shots in 25p, then did a 120/25fps. After recording I switched into Playback mode and showed the last shot (slowmo) to the client. Then powered down while still in Playback mode. Bang - got the error message in Windows.

The same happend a few days ago - powered down while in Playback mode. Bang - error message.

Maybe others here can do a similar test and see if they can reproduce this behavior?

Seems like the camera OS is messing with the file structure while playing back and doesn't finish that thread when powering down.

Ah ha. You might just be onto something. I'm going to test your theory and get back to this thread.

Also, I've only had problems with 256GB cards (Lexar, Crucial). My 128GB cards have been rock solid. Have you had this problem with anything other than 256GB cards?

Tristan, I've got only 256 GB cards. Two Lexar 3400, one Transcend 650, and the two Angelbirds.

I had problems with both Lexars and now with the Angelbirds. The Transcend got not much use, so I can't say. I will do some further tests with all cards.

My Cards Lexar 3600s occasionally corrupt doing the same thing... also i have 2 mini pros ... occasionally swapped cards accidentally and it has corrupted a card reading "initialize card"...Data rescue 5 recovered file beautifully..

The same thing happened to me on two different (consecutive) productions. First time I think I did the same 25fps, then 120, then playback as you did, Robert!

Also using two Lexar 3400x, but the 128GB versions.

I discussed about the issue with BM support but couldn't find the source of the problem since it didn't happen ever since. It did however make me super paranoid and turned me into a backup freak on set.

BTW, the first time I did manage to recover the partition - with MiniTool if I remember correctly. But the second time I had to do a deep file recovery and got some unordered DNGs.

Where you shooting RAW 3:1 too?

this an old and worst problem with windows, from many years (over twenty) i fight with this issue, when windows see some strange infos in mbr or garbage in some sectors it start to ask and try to adjust something that cause in 70% of case damage to datas or to a support.
for this reason i prefer to use macOsX to manage files, and i try to not use windows and whe i use it i modify regedit to avoid this annoing situation.

go to HKEY_LOCAL_MACHINE\SYSTEM\CURRENTCONTROLSET\CONTROL\Session Manager
double click on Bootexecute
change original autocheck autochk *
in
autocheck autochk /k:C /k:D /k:F /k:E /k:G /k:H /k:I /k:L /k:M /k:N /k:O /k:P /k:Q /k:R /k:S /k:T /k:U /k:V /k:Z /k:X /k:W /k:Y /k:K
this mean never check no one disk letter. If you desire to leave autocheck on some disk, just delete letter of disk.
save and reboot.

this an old and worst problem with windows

In my case the card appeared not to be formatted in the camera right after clip playback without previously touching any other workstation so I doubt that it's a Windows problem.

this an old and worst problem with windows

In my case the card appeared not to be formatted in the camera right after clip playback without previously touching any other workstation so I doubt that it's a Windows problem.

in both file system?
unfortunately bmd (and not only) choose exfat and not NTFS FS which is a stronger file system for windows compatibility,

i (luckly) never seen this bug, first be cause i never turn off during playing clip, and later be cause i use only HFS+ file system which is hardest to break, i can read it directly from mac, and with 15 $ driver from paragons under windows.

do you see this issue on both fs? i'm not near a camera to test it.

NTFS doesn't prevent that corruption - you can get this with NTFS drives too. And Microsoft doesn't license NTFS to third parties.

NTFS doesn't prevent that corruption - you can get this with NTFS drives too. And Microsoft doesn't license NTFS to third parties.

to be honest, i talk for me, about the last twenty years, every times happend to me, to my friends, are only on fat, fat32, exfat drive, never on NTF or HFS+ fs.
if happened also to ntfs, bad notice...

So - I did several tests and every time when shutting down the camera when still in playback mode - I'll get reproducible the error message in Windows.

Doesn't matter if I recorded off-speed slowmotion or normal speed.

Cards are formatted to ExFAT.

So - I did several tests and every time when shutting down the camera when still in playback mode - I'll get reproducible the error message in Windows.

Doesn't matter if I recorded off-speed slowmotion or normal speed.

Cards are formatted to ExFAT.

good (bad) to know what we must not do...
Thanks Robert