Bought the Droid approximately 3 weeks ago. Have gotten all the updates. I have never installed Handcent, but I had installed the "SMS unread count" app.
Since day one my settings have dictated no limit on my SMS messages and to never delete anything.
The first time happened one week ago. My Droid froze up, so unable to reset it, I had to pull the battery out. Once i replaced it, all my messages were gone. I can't remember what I was doing to make the Droid freeze, because it had never behaved poorly until then.
The last 2 times happened close together, within the past week. During both times, I was using the messaging app, and recevied a "SMS Unread Count app had unexpectedly quit" error which forced me to close. Immediately after that, I found all my messages had been purged. I have since deleted that particular application (yesterday) and am waiting for it to happen again.
Looking for a good SMS backup app.
-ww