5D3 - CF card randomly needs formatting?!

[CinematicSyndicate]

I am using one of the new nightly builds on the 5DIII for raw video. I am typically recording at 1920x818 sustained with no frame drops. Every once in awhile I will power the camera down, and come back to it later to use it - and when I boot the camera I get an official Canon GUI message stating the card is unreadable and needs formatting.

Because of this I lose ALL of my RAW files and all data on the card, and my PC reports needing to format it as well to make it readable - which of course further deletes any data that may still be on there...card recovery programs have no idea how to get the files back because the .RAW header structure is not one typically recognized by the programs....help! I am gearing up for a short film production shoot and need to be seeing reliable tests from the camera.

[hjfilmspeed]

what build, what card are you recording to? how do you format it (fat 32, exfat) what card is ML on? Are you keeping them separate.

I can tell you with my set up i have never encountered this and i have been shooting raw for months now with no issues.

[RenatoPhoto]

Probably the card is on its last leg, maybe camera CF reader is dying.
Try another CF card first.

[CinematicSyndicate]

hjfilmspeed - I just purchased a new card, it's a Sandisk 32gb UDMA 7 120mb/sec card. I realize it's not the best choice for ML RAW. I will be purchasing a Lexar 1000x shortly to replace it. So it's a brand-new card, which is strange.

As for the build details: it's build v2.3.NEXT.2013Aug22.5D3113, Compiled on 2013-08-22 01:24:53.

I am formatting exFAT on my Windows 7 PC, then using EOS CARD program to ready the card for action. I then copy this latest firmware to the card with all other necessary data. ML is on the CF card (only card in camera). Last time I ran ML off an SD and used the CF for recording, the camera was acting a bit funny...although I may have had ML on both cards and configured it incorrectly - not sure. Is exFAT faster, or is there any advantage to using that (other than non-splitting files)?

Do you notice anything inconsistent with your setup that has run well for awhile?