If you have been doing your routine maintenance compacting messages, and you are still having problems, it sounds as if your .DBX boxes need to be cleaned out.  To do this, basically, you will backup OE folders (to be deleted later.) Close OE. Delete the hidden folder(s) causing the problem, and when OE loads again, it will be rebuilt with those folders empty so you can start fresh.) You did not mention your operating system, so I cannot give specific steps.  Maybe this will help: [URL]  <-- There is a link in this discussion to more details.  [URL]
I had accumulated several hundred emails and was going through them deleting one at a time. During this process the delete was woking fine deleting each one as I clicked on it then hit delete on my keyboard. All of a sudden it would only delete certain emails. Some it would most it won't. Have any of you seen this problem and can help me get my emails deleted? I have tried all the other options for the delete function within Outlook Express. Thank you very much for your time and help with this. Sincerely Stanee  
Oulook Express-Delete Function