Am i doing something wrong when recording? Pushing record then stop too fast by accident? Sometimes I have no 0 kb files are shooting, other times like today I have 10 with my other 35 shots. What causes this? I`m using the FS 4 PRO HD

As far as I can tell this is normal. Whenever I record with my FS-C, I always end up with a few 0kb files. They contain a single frame of SMPTE color bars and exist in addition to the clips I've shot (I've never had clips that I've shot get corrupted or go missing). In other words, these seem to be *extra* files. I should look at the manual again though because I don't remember reading an explanation of why the Firestores generate these files in the first place.