The drive content isn't checked and verified, aka audited, on boot. My HR44, with a 6TB array and only 30% available takes the same amount of time to boot as when I first got it and that's just over 2 minutes.
So, you think that what you think you might have seen is enough to invalidate actual facts? Good luck living a life like that. Are off-hand comments by readers on WebMD enough to get you to dismiss direct advice from your heart surgeon, because what Joe Sixpack posted there must mean someone who has studied the issue and worked with it professionally for a long time hasn't a clue? Why am I not surprised by that?
Every DVR from the beginning of time has done this. It prevents corrupted files from mucking up the system. IOW, if it can't rectify a file based on info it compares it to in the database, it deletes that file during the start-up sanity check so that such a file can't cause issues down the road. But it has to check each file for continuity serially, one by one, and that includes separate audio files if they are not interleaved with the video. And this is from the legacy of professional broadcast video servers (which is where DVR technology came from, BTW), which have been doing this for decades, and which I am paid pretty handsomely to be this familiar with.
If it was not done, there could be files that were still listed, yet they will not play properly or at all and can't be deleted, which means over time every DVR playlist would become a mess, since unlike professional media servers there is no preventative or regular maintenance done on DVRs once the consumer has them, and call center phone calls would triple, and that does not begin to touch the number of issues that corrupted media files might cause, including spontaneous reboots and unrecoverable crashes.
Not only that, but my array is MUCH bigger than your array (OK, like most of the rest of us I don't need to overcompensate for imagined shortcomings, so I'm not nuts enough to think I even need an array, or a pickup truck with giant wheels that's 8 feet high).
Knife to a gunfight?