BMPCC 4K deleting my files

Hello internet,
I have been having this problem where I record on my BMPCC4K, and then I go home to transfer the footage only for nothing to be there. This has happened to me three times now, luckily each time I was recording a rather inexpensive B-roll shot but there are times where I am recording all day very expensive (for me) short films and I cannot have this happen then.
The first two times this happened I was shooting onto a T5 SSD formatted to exFAT. Trying to solve the problem I started shooting to a CFast card formatted to macOS Extended (Journaled), but the problem persists.
So my question is how can I prevent this from happening again? I believe a contributing problem may be that I did not format the card the last two times it has happened (I cannot recall if it was formatted for the first time). Do you think it could just be a fluke accident that happens when the card is not clean or something else?
Thanks for your help.

Link to post from last time this happened:
https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=184874

Always format in camera, don't use exFAT, and have the camera stop on dropped frames.
If it still happens, you may have a defective storage. But check your cable first.

I believe a contributing problem may be that I did not format the card the last two times it has happened (I cannot recall if it was formatted for the first time).

FORMAT YOUR CARDS IN YOUR CAMERA BEFORE EVERY USE

I cannot stress this enough. Every time you use a piece of media, whether it's SDXC, CFast, CFExpress, USB-C drive, format it in the camera. Don't delete files and just slap the card back in the camera. Format it. In the camera.

And like other folks have said, if you're running MacOS then HFS+ is a better option than ExFAT.

It’s safer to use even for Windows. There’s software to access it, like that from Paragon.

Thanks all,
I was already formatting my card for any big shoots I was doing, but some of these small low stakes ones I have not been too diligent about it but that will definitely change now.

I've got the gut feeling we are not getting served the whole picture here about what's going on.
Never ever in 11 years of shooting with Blackmagic cameras (BMCC, 2 PCC4ks, 1 PCC6k Pro, UM46k, UMP G1) did I encounter a similar problem. All media formatted to exFAT.

The cameras itself are not capable of deleting anything - except when you format the media in camera.

In the other thread Ethan wrote, he first could playback the footage in camera, but after plugging the T5 to his Win PC, the footage was gone and then couldn't be played back in camera, too.

If the camera is behind this phenomenon then a firmware downgrade could be tested if it solves this.
I had the case, when I did the playback in one of my BMD cameras, then shut off the camera without going back into REC mode, Windows would see the media in need for a checkdisk repair. Didn't lose any footage, though. I think this was with the UM46k, but am not sure.

Then there could be an issue with Win 11 or that specific PC Ethan is using, or the cable/cardreader. Or there is some software interfering.

BTW - same thing can happen with an ARRI Alexa:
https://forum.arri.com/viewtopic.php?t=1589

There is also an UDF issue with Win 10 and Win 11:
https://forum.arri.com/viewtopic.php?t=1464

That got fixed by Microsoft 1 year later. Before that I couldn't read my Compact Flash cards from my Canon XF305 camera on my Win 10 PC (only my old Win 7 did read it).
• Windows 10: 2022-06 Cumulative Update KB5014666
• Windows 11: 2022-06 Cumulative Update KB5014668

It also depends on the negotiation between the reader hardware and Windows, which determines if a memory card is attached as removable media or external disk.

So I think if you want to find the cause you will need some kind of a systematic approach.

I have had that kind of problem on an UMP G1 , using Exfat and CFAST Cards .. never had the explanation , so I now use HFS+ , and never had that problem again ..

On Windows , you can use HFS Explorer , which is free , simple , and works very well .. never had a problem with it

Windows seven is a rather old Os , it may be 32 or 64 bits .. Windows is " so - so " .. in some ways sophisticated but not always very reliable .. It's a good idea to have a PC with Linux installed .. if you know how to use the Command Line , in the Terminal , also named the " Konsole " , you have many useful tools which help you to understand problems .. Also , about Usb Devices , most of them are Natively seen by Linux , no Drivers problems ..

And " De la Méthode avant toute chose " .. Of course , before doing any serious work , Test , Test , Test again , to get a reasonable Certitude everything works as it should ..

My Two Euros ..... / Mike ..

The problem is probably that you are removing the media too fast after powering off.

When you are inserting the computer it comes up as format drive? You can use ChKDSK to fix the file table.