Responding to my own post ....
Since this original post in 5/2010 I have been using the same card without issue. Fill it up, empty it, reformat, fill, empty .... It has performed without issue for hour after hour. Now, for the 2nd time I had the "file damaged" message when I checked during recording.
I was using 48/24. I estimate I was 1:45:00 +/- into the recording. I hit record to resume, of course a new file is created, and the previous one remains, but is not accessible. Is it gone? or how can you get at it? or does an error simply eliminate all data if the file is not closed via the 'stop' function?
That the card has performed reliably for over 100 hours, has been swapped in and out, reformatted and shown no problem for the past 8 months .... what is up with this?? Is it the M10 or the card?
More importantly, is the data ever recoverable? How?
Salt in the wound ... where i was taping last night someone shows up with a D6 walkman. I remember mine fondly, still have it but needs work. I know damn well he only had to flip the tape but at least he wasn't plagued by a digital demon and walked out with a complete show.