"tvman8816" wrote:it had destroyed my data file and did not back it up as far as I could tell...
First of all, the upgrade is totally safe it DOESN'T harms any data. Versions 2 and 3 are 100% compatible, you can freely upgrade/downgrade without limitation of any kind.
I'ts hard to say what exactly happened from your words, but sometimes on upgrade users are managing to create new (empty) data file. Which give an impression that the data is lost. I'ts not lost, but you need to open your old data file using menu item File -> Open, as simple as that.
Also, if to presume that somehow data was lost (which I totally deny), you can recover from a backup. By default AllMyNotes creates lots of backups, every few hours, and keeps them all for at least 4 days. So there is no way for you to loose many data even in case of very major data file corruption, you just need to do search for file with *.ddb extension on your disk(s), you'll find many backups and, hopefully, your original database file from version 2.xx, and open it by double-clicking on it. Once good data file found you can give it more appropriate name and location using menu item File -> Save As...