Things to try. Start, however, with making a copy of Inbox.dbx in Windows Explorer, so you can always go back to the current situation by copying it back.

1. Retrieve the last good version of inbox.dbx from your backup. That's exactly what you make a backup for, as described in (if you don't use one of the many specialised backup programs available).

2. From Outlook Express: File>Folder>Compact the Inbox. It won't harm to compact all folders. How often do you do this?

3. Try a repair program found by
They might not be free. Be sure to copy your copy of inbox.dbx over the compacted one you made in stap 2, if step 2 doesn't help. After compacting, no program can retrieve anything, so you have to go back to the original situation.

4. Make a copy of all folders, then import as described in the MS article above. It's a minor chance that the import will be able to read messages that OE can't normally find, but it won't harm to try.

Hope this helps.