How to remove email threads from Outlook quickly?

Author Kelly Last modified 2025-04-03

Sometimes, you may discuss with others via emails in Microsoft Outlook. For a long time, the response back and forth are many and redundant, because the last one includes contents of all replies. Here I will show you how to remove redundant email threads from Microsoft Outlook easily.

Remove redundant email threads with Clean Up feature

Set exempt for cleaning up in Microsoft Outlook

Remove redundant email threads with Clean Up feature

The following guidance is about how to show all emails as conversations, and then clean up conversations quickly in Microsoft Outlook 2010 and 2013.

Step 1: Click to open a mail folder that the email threads stay in.

Step 2: Check the "Show as Conversations" on the "View" tab.

the Show as Conversations checkbox

Step 3: In the popping up dialog box, click the "All mailboxes" button or "This folder" button.

the popping up dialog box

Step 4: Select the conversations that you will clean up from the mail list.

the conversations

Note: You can select multiple conversations with holding the "Ctrl" key and clicking each one separately.

Step 5: Then Click the "Clean up" > "Clean Up Conversation" on the "Home" tab. See screen shot below:

the Clean Up Conversation button

Notes:

If you want to clean up all conversations in current folder excluding those in its subfolders, please click the "Clean Up" > "Clean Up Folder".
If you want to clean up all conversations in current folder including those in its subfolders, please click the "Clean Up" > "Clean Up Folder & Subfolders".

Step 6: In the coming Clean Up Conversation dialog box, please click the "Clean Up" button. And in the following Microsoft Outlook dialog box, please click the "OK" button.

result 1

Set exempt for cleaning up in Microsoft Outlook

If exempts of cleaning up conversations exist in your Microsoft Outlook 2010 and 2013, please do as following:

Step 1: Click the "File" > "Options".

Step 2: In the Outlook Options dialog box, please click the "Mail" in the left bar, and then go to the "Conversation Clean Upz' section.

the Outlook Options dialog box

Step 3: Check one or more exempt options as you need in the Conversation Clean Up section:

If you want to keep unread threads when cleaning up conversations, please check the "Don’t move unread messages";
If you don’t want to clean up threads marked with categories, please check the "Don’t move categorized messages";
If you don’t want to clean up threads marked with flags, please check the "Don’t move flagged messages";
If you don’t want to clean up threads with digitally-signed, please check the "Don’t move digitally-signed messages";
If you don’t want to clean up threads with changes, please check the "When a reply modifies a message, don’t move the original".

Step 4: Click the "OK" button to exit this dialog box.

Note: Microsoft Outlook 2007 does not support the Clean Up conversation feature.