Cannot delete a message

When trying to delete a message, it could be that Outlook refuses this and shows an error message. Most common error messages are;

“An unknown error has occurred.”

and

“Messaging interface has caused an unknown error.”

There are 4 easy methods which you can use to solve this for most situations.

Note:
If you have a message stuck in your Outbox see; Message stuck in Outbox.
If you get the error “The Folder is full” see; Folder is full.

Method 1 – Empty the Deleted Items folder

The easiest method is to first empty the Deleted Items folder and then try to delete the message again.

A quick way to do this is by right clicking on the Deleted Items folder and choosing “Empty folder”. You’ll also find this command when you select the Deleted Items folder and then select the Folder tab of the Ribbon.

Method 2 – Hard delete the message

You can also “hard delete” the message by holding the SHIFT button while clicking on the Delete button or using the Delete button on your keyboard.

This message will now skip the Deleted Items folder and will directly be permanently deleted. Outlook will display a warning if you really want to do this.

Method 3 – Edit the message

By editing the message first and saving it, you could reset a particular corruption of the message which allows you to remove it normally afterwards;

1. Open the message by double clicking on it.
2. Place the message in edit mode;
   • Simplified Ribbon (Microsoft 365)
     Press the ellipsis button (…) on the right side of the Ribbon to expand it-> Actions-> Edit Message
   • Classic Ribbon
     Actions-> Edit Message
3. Type or remove some characters (I usually type 3 spaces).
4. Save and close the message.
5. Try to delete the message again.

Method 4 – Scan your pst-file for errors

If the above methods fail, the issue could be caused by a corruption within your pst-file. To fix this issues, run scanpst.exe against your Personal Storage (pst-) file. The location of scanpst.exe depends on your version of Outlook and Windows.

For an overview of the possible locations see; Inbox Repair Tool (scanpst.exe) or use OutlookTools (free) to locate it for you.

If you do not know the location of your pst-file, you can use one of the following methods to locate it;

• Make sure you include hidden and system files and folders when searching for pst-file
• Default locations are;
  • \Documents\Outlook Files
  • C:\Users\%username%\AppData\Local\Microsoft\Outlook
• You can also locate the file in Outlook by using;
• File-> Account Settings-> Accounts Settings…-> tab Data Files

For a complete step-by-step tutorial about using scanpst.exe see:
Using the Inbox Repair Tool (scanpst.exe)