You need to check if the problem is caused by a corruption of the Outlook Express dbx data file, or caused by other reasons. To do that, you need to do as follows:
1. Locate the dbx file corresponding to your mailbox, by following the instructions below:
2. After locate the dbx file, make sure Outlook Express is closed.
3. Make a backup of the dbx file.
4. Delete the original dbx file.
5. Start Outlook Express, if you still get the same error, then chances are that your installation of Outlook Express is incorrect. You need to uninstall and reinstall Outlook Express. Note Outlook Express is included in IE so you may need to reinstall IE together.
If the error never appear, then your original dbx file is corrupt, you can use DataNumen Outlook Express Repair at https://www.datanumen.com/outlook-express-repair/
to repair and recover the emails in it, and then import the recovered emails back to Outlook Express by following the instructions at https://www.datanumen.com/outlook-ex...air/import.htm