0x800420CB - Message Could Not Be Opened From Outbox Folder

0x800420CB - Message Could Not Be Opened From Outbox Folder.
You will need to rename the Outbox file which deletes all emails in that folder.

1. Remove all mail accounts from Outlook Express.
2. Click Start > Find > Files or Folders
3. Search for outbox.dbx in the C: drive.
4. Right-click the Outbox.dbx file, and click Rename.
5. Rename it outbox.old.
6. Click OK.
7. Start Outlook Express again.