How to Hide Strikethrough Messages Marked for Deletion in Outlook 2003 [IMAP] 

Why "Delete" Does Not Mean Immediate Deletion

One of the quirks of IMAP in Outlook 2003 is that messages are neither deleted immediately when you press Del nor moved to a Trash folder but "marked for deletion" until you purge the folder.
In the default view used by Outlook 2003 for IMAP accounts, this has the consequence that "deleted" messages are displayed greyed out and with a strike-through line. But they are still visible. Now, either you purge your inbox constantly, or you deal with the irritation of lots of messages that are, in a way, undead — or you tell Outlook to hide these messages.

Hide Strikethrough Messages Marked for Deletion in Outlook 2003

To hide messages already marked for deletion in Outlook 2003: 
select View | Arrange By | Current View | Hide Messages Marked for Deletion.
Purge Deleted Messages in Outlook 2003

To purge deleted messages in Outlook 2003: 
Select Edit | Purge Deleted Messages from the menu. 
Click Yes. (Keep in mind that this command removes deleted items only from the current folder)

If selecting from the menu bar seems a bit too much work for so often used a command, you can place a Purge button in your Outlook toolbar:
  • from the menu Select Tools | Customize
  • Go to the Commands tab. 
  • Choose Edit under Categories. 
  • Drag Purge Marked Items in All Accounts (or the equivalent commands limited to the current account or folder, or Purge Deleted Messages in Outlook 2003) from the Commands: column to the desired place in your toolbar.
  • Click Close.