Slightly OT but there does not seem to be a VIRB hardware specific forum...
Just a hint for those of you who have experienced the VIRB crashing.
When a crash occurs, the Flash card file system (either FAT32 or exFAT) may be left in an inconsistent state whereby the video file being recorded at the point of the crash appears to be the wrong length (sometime zero bytes) yet the available space on the VIRB flash card has reduced.
To recover the space - use Disk Utility to first Verify and then Repair the Flash drive (sort of equivalent to CHKDSK in older Windows variants).
(You may need to close VIRB Edit and unmount then remount the card for the Repair to work)
Note that this means all of the Flash drive blocks holding the video file associated with the crash are marked as free (i.e. the video data is lost).
NB The VIRB (at least v2.60) does not appear to scan the Flash drive on startup.
Hope this helps.