memos disappear

I have a user who has a Handspring Visor running Palm OS 3.x. Their memos have disappeared on the handheld, but everything else (addresses, datebook) remain intact. Unfortunately when they sync with palm desktop, it erased the memos there as well. I thought it was odd that just the memos vanished and not any of the other data. Has anyone else experienced this, and if so, do you know what caused it and did you find a solution?