Something funky with the 2 gig autosplit last night. New, untested SD card may have been the culprit, haven't been able to reproduce it. But I was in dual recording mode and when the recorder hit the 2 gig limit, the timer froze at 2:15:xx (whatever 2 gigabytes is at 24/44.1) with 0:00 remaining, but the record icon was still displayed, the levels behaved as normally in response to the input sound, and the record light stayed lit. No response to any button pressing. Eventually, over an hour later, it displayed a "file error" message and became responsive again, but could not play back the files. They display on my computer as 0 kb files, although the remaining disk space seems about right for 2 x 3 hours of 24/44.1 audio being present. No luck with any recovery tools tried to date, or opening the files in Sound Studio or Audacity.
Kind of a bummer. Will try to manually start new files before the 2 gig limit whenever possible in the future, just in case. But will do more testing at home seeing if I can reproduce this weird error.