Save changes to this message?

When I close a message, I often get this question. I’m not aware of making any changes to it.
What changes is it trying to save and how do I get rid of it?

There are 2 main reasons for this to happen. The first is that you have downloaded any pictures from the Internet (manually or automatically) that were included within the message or that you have opened an attachment of that message.

In case of the first, as downloading the pictures for an email item is considered a change, you’re prompted for the message to be saved.

In case of the second, when you open a message first and then one of its attachments, you’re opening this attachment in with read/write access to it and the message holds a link to it too. This enables it to save changes to the attachments that you have made within the original message. Some applications, that you open the attachment with, immediately mark the opened attachments as “dirty” (meaning that a modification has been made to it). Because of this, even when you don’t change anything to the attachment itself, Outlook will still ask you to save the changes.

To work around this behavior, you can opt to always open the attachments from the Reading Pane instead of from an open messages. In Outlook 2007, you can also configure Outlook to always open the attachment as Read Only. However, this setting can only be changed via the registry;

Key: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Outlook\Options\General
Value name: OpenAttachmentsReadOnly
Value Type: REG_DWORD
Value: 1

When this key is set to 0 or missing, attachments opened from the Reading Pane will be opened as Read Only and attachments opened from an opened message window will be opened in Read/Write mode.

Note: For this registry key setting to work, you must have either the latest updates of Outlook 2007 installed or at least Hotfix package: June 11, 2008