Some people like to keep their Outlook folders perfectly controlled, with emails neatly categorized and stored in a logical, minimal folder structure. Most of us aren’t like that, so Microsoft has provided tools to help. One of these tools is the little-known Conversation Cleanup tool, which deletes or moves redundant emails from a conversation. Here’s how it works.
You can run the Conversation Clean Up tool against a single conversation, a folder, or a folder and all of its sub-folders. It looks for emails that are redundant, which mean those that are included in full in another message in the conversation. It then deletes (by default) or moves these emails to another folder, depending on how you’ve set it up. This helps keep your mailbox from being filled with multiple copies of the same message.