Same problem for me described in the first post of this thread. I'm using a Micron 7300 U.2 3200gb SSD, from the list.
What I learned is that my Ursa 12K (bought after the price drop) formats the hard drive to a MBR partition style. Had no clue what that is and based on some research it seems to be the older style and is not capable of using bigger partitions than 2TB.
"If the capacity of your hard drive exceeds 2TB, you should choose GUID partition table (GPT) partitioning scheme, so that you can make use of all storage space"
Here is also a video on the subject of MBR vs GPT
When I format my Micron 7300 U.2 ssd using the Ursa 12k to ExFat, my windows workstation can't read it. The drive does show up in the disk manager, but not in file browser. I get the exact same thing as in the picture in the first post, weird partitions of under 2TB. The drive works in the camera though and can record video etc, I just can't acces the files.
If I however format and covert the drive to GPT I do get the full 3TB space and the workstation can read the drive normally. Yey! The camera can also use the drive and it works, but it does take longer for the camera to recognize the drive. It takes maybe one minute for the camera to recognize the drive when I turn it on whereas it finds it in like 2 seconds when the drive is formatted to MBR.
So just formatting the drive on th pc and choosing GPT partition style did kinda work in the first quick test, but the camera does behave differently. I don't know if that matters, but it makes me want to ask what the proper way of going about this is? Pretty confusing. If the camera needs the MBR style partition it formats to then how am I supposed to access my files? Also, it should obviously be mentioned if the camera is not capable of using more than 2TB drives, especially when bigger drives are promoted in the manual. If the GPT partitioning actually is a legit way, then that's great! Just super weird in that case the camera doesn't format to that by default.
It feels super weird how this file management can be so complicated. Also for me there is no other way to read the U.2 ssd than taking it out of the camera/SSD recorder and using a fishy cheap looking third party U.2 usb dock reader which was the only one I could find and connect that to the pc usb slot. Pc can't find the hard drive when trying to hook the camera or SSD recorder to the pc using an usb-C cable. A BM reseller here told me it is not even supposed to work, but here someone said they always connect the SSD recorder directly to pc using a usb-C cable and that way import the files to pc. I don't know, there are so many different experiences and advices that it is very unclear how this is intended to work with the 12k.
Just in case to not bury the most important question: Can I use GPT partitioning scheme when formatting?