Some people keep their Outlook folders under control by neatly categorizing emails and storing them in a logical, minimal folder structure. Most of us are not, so Microsoft has provided tools. 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 Cleanup tool for a single conversation, folder, or folder and all its subfolders. It looks for emails that are redundant, those that are completely contained in another message in the conversation. It then deletes (by default) or moves these emails to another folder, depending on how you set it up. This will prevent your mailbox from being filled with multiple copies of the same message.
First, you need to set the conversion cleanup parameters. Go to File> Options> Email and then scroll down to the Conversation Cleansing section.
Conversation Cleans deletes items by default. However, if you want to move redundant items to a folder, you can click Browse and select the folder to which you want to move it. This is useful if you want to check yourself if the messages found by the tool are really redundant. The Conversation Cleanup Tool is, in our experience, reliable, but sometimes there is no substitute for checking things themselves.
You can probably leave the other default options as they are because they make sense But if your situation or preferences are different, go ahead and turn the parameters on or off as you see fit. Once you have made the desired settings, click "OK" to return to Outlook.
Now you need to open the tool. On the Home tab, click the Purge button. The drop-down menu allows you to clean up the currently selected conversation in the folder, in the entire folder or in the entire folder and in all subfolders.
You can access it as well. If you do not need the Clean Conversation option, click Folders> Clean Up Folders on this menu.
We're going to clean up with "Folder" now, but it does not matter if you're cleaning up a conversation, folder or folder and its subfolders. And for a one-click option, you can always right-click on a folder in the navigation pane and select "Clean folder".
When you run the tool for the first time, a warning is displayed. This allows you to change the settings, run the tool, or cancel the operation.
If you want the tool to run without this popup, check the "Do not show this message again" option. Option
Click Clean Up Folder to run the tool (if you have turned on the "Do not show this message again" option, the tool will run from that point on). When the tool runs, it may take a while to first run it in a folder with many messages. A status notification appears in the bar at the bottom of Outlook.
You can still use Outlook while it is running. As soon as the status message disappears, the tool is finished. It will not tell you it's done – the tool is designed to run in the background to help you not bombard you with messages – but it will tell you if it can not find any messages can be cleaned up.
That's all that goes with it. When running this tool in an example folder with 2487 emails, we found 502 emails that could be deleted. More than a fifth of the emails in the folder were superfluous, so it's an eye-opener and a tool that's worth using when you run out of space or wading through conversations.