In OE, the most vulnerable folder is the Inbox, should OE crash for any reason, it often corrupts the In Box (thats the one that is usually open when it crashes). When OE is restarted, because the Inbox is a special OE Folder it is re-created.
There are many different tools to try and recover data from corrupted OE .dbx files, they don't always recover everything.
Currently there are only 4 emails in my Inbox folder, don't use your Inbox folder to store emails. Use it as temporary point prior to moving it to a folder for that type of email. Such as Business, Personal, Newsletters, etc.
Not only does this make emails easier to find, if your Inbox does get corrupt, not much is lost and then you can try your backup strategy - the recovery tool - don't have the tool as your only backup strategy.
David