Archiving on Microsoft Outlook 2010

Google Apps is my primary choice for email at home, however Microsoft Outlook 2010 is the staple mail client supplied on my corporate laptop. We’re pretty lucky as the mailbox limit is pretty large, compared to all previous organisations I’ve worked for – I’ve had anything from 50MB, to 150MB on average, but even my current 2GB limit won’t hold everything. Since starting at Savvis in 2011, I’ve adopted an archive everything policy, rather than deleting any messages – this has been and continues to be a very useful source of information, as a record of all previous conversations, but also as a reference library.

The downside to effectively keeping everything you send and receive, is that it has a constantly growing storage requirement – the old data needs to be taken out of the mailbox, and stored off-line in PST files. If you’ve ever used archiving in Outlook, something you may not have realised is that messages are archived based on their received date and the last modified date and time, whichever is later. This is a problem in the way I work since I move messages between folders and update categories on a regular basis, all of which affects the last modified date. I’ve have also recently been trialling Taglocity and re-tagging a lot of mail which has ended up changing the last modified date on 95% of mail currently in my mailbox – when I ran an archive on all mail over 3 months old, hardly any mail was moved out to the archive.

Fortunately, it is possible to change the default behaviour by adding the following registry key:

Key: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
Name: ArchiveIgnoreLastModifiedTime
Value: 1

This will remove the check against last modified date, and only check against the received date when processing messages as part of the archive process. In Outlook 2010, this feature was added in KB2516474, so you need to make sure to have this patch installed. Once I had made this change and re-ran archive, 600MB of data was now moved out to my local PST. More information on this registry change can be found in KB2553550.