It happened again - disastrous data corruption. Last time it involved my email client (icedove) on my own Linux box. This time it was my wife's email client (Outlook Express) on her Windows machine.
It started when OE asked me, upon being closed, if I'd like it to compact its folders in order to save disk space. This kind of maintenance is recommended by Micro$oft in order to prevent corruption of the message storage files. Compacting is also known to cause corruption...
And guess what? it did. My wife's Inbox, very much like her desk, is filled with stuff - more than 8000 messages. After compacting was done, only 6000 messages were left - 9 months worth of emails were lost.
If this ever happens to you and you're running Windows XP and up than you may be able to restore the original dbx storage files - OE places a copy of the original files in the recycle bin before compacting (but with a .bak extension instead of .dbx).
I didn't know this at the time, so I went ahead and restored those email messages from the Bacula backup. As I described a while ago, I have an elaborate backup procedure that backs up individual email messages instead of the gigantic dbx files. After restoring the messages to a temporary folder on my wife's PC, I simply selected the missing messages (eml files) in Windows Explorer, and then dragged and dropped them into the Inbox folder in OE.
It took a few minutes, but OE (and I) survived this ordeal.