I have a JVC HD-GY201 and Firestone DR-HD100 DTE unit.

Two similar issues in two consecutive shoots indicates that I have a problem - I am missing video files on the HD100 unit.

Scenario 1:
Shooting a sports event in the field with lots of short clips - constant stop/start record.
Got home and am missing an interview with a race winner. Have the clip before, and the one after, but not the interview.

Scenario 2:
Shooting a stage play in a theatre. Start recording Act 1, and stop about 80 minutes later. Same again for Act 2. Replaying the performance, I am missing the first 13 odd minutes (which is the length of a 2gb file recording M2T @ 720p/25p).

I am experienced enough to automatically check the recording indicator is red after pressing the REC button (and reverse for off).
No corrupted files - connections all good.
Before each shoot I format the DTE hard drive - no individual file deletion.
Being an IT person, it looks to me like the missing files have been over-written.
If so, then it would seem the problem is with the DTE unit.
But each file has the timestamp as part of the file-name, so to over-write it would have to recreate the same file-name. Which doesn't make sense to me!

Now I read that most people use a tape back-up.
OK, I haven't done that as it has been rock solid reliable for 1.5 years that I have had the camera.
But tape back-up will be my short term contingency.

Has anyone else had a similar experience? Is it the DTE device?

Update. I had two shoots on the week-end. Athletics on Saturday, then an actual performance of an amateur theatre musical on the Sunday.

For athletics, ran a tape as back-up. Not aware of losing any clips.
For theatre, had no tape back-up, but had a 2nd camera (one cam for wide, one for close-ups). No lost clips again. (Also gaffa taped a gopro cam in the orchestra pit - trippy results which look to be good cutaways during scene changes etc.)
After starting up camera on each occasion, I formatted disk then and there before recording (instead of doing it the night before).

Hmmm. Not sure what's going on. But if I wear blue underpants, make sure the moon is aligned with Mars, and drink with my left hand, and it all works, I'm not going to argue.

Will continue to monitor, and run a back-up tape for time being.

Whenever you can, record to a back-up tape.
I've had camera assistants who forget to turn on the hard drive...
They've not lasted in their position, but the damage was lessened because of tape backup.

David-

So sorry to hear of the problems you are experiencing. I don't think there is anything worse than lost footage. I have exactly the same setup as you and always shoot to both tape and harddrive -not only due to redundancy but also because I can archive the tape afterwards. However the rising cost of tapes and lack of availability means this may not last much longer!

I have experienced lost clips on the DR-HD100 but I think due to different reasons. Firstly, the most common reason was due to the harddrive shutting down without my realising it. I now have a system in place which I always double check but even then there have been one or two occasions (for which the tape was a life saver!). Then over a year ago I was experiencing intermittently corrupted clips, with dropped frames and then audio sync issues. At times, I would have to go back to the tape to recover the footage. But I had the camera serviced and it was discovered that there was an issue with the camera's firewire port, and ever since that was repaired I have no longer had any issues.

I recommend that if you have someone who regularly and reliably services your camera that they take a look. Such an intermittent and critical fault is definitely something you would want sorted out.

Thanks for replies.
Tape back-up will be the standard procedure going forward. I suppose as it is a "bolt-on" unit, rather than integrated into the camera, there are bound to be some issues from time to time.