When you copy an email to OURDrive, you are keeping a copy in Outlook as well.
Select the email you wish to copy to OURDrive. From the ribbon, select the Home tab and click in the top half of the Copy to OURDrive icon to save this to your selected library. Or click on the bottom half to select a different library.
Alternatively, you can right-click on a message and choose Copy to OURDrive from the right-click menu, or drag and drop to a storage folder while holding down the Control key on your keyboard.
The Save to SharePoint dialog will be displayed. Locate and click the location where you wish to copy the item to in the left-hand pane.
From the right-hand pane, set the Content Type (usually OU Email) and fill in properties as necessary.
Click the Save button. The file will be copied to OURDrive and a confirmation message will appear. The mail message will be retained in Outlook. Click the Close button to close the confirmation message.
Your email will now have a category applied to show that it has been copied to OURDrive.