How To Set Up AutoArchive For Outlook

BigArchive AutoArchive ensures that your Outlook email file doesn't get too unwieldy, but the default settings aren't necessarily very helpful. Here's how to make sure your email is backed up into archives successfully.

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Online email is increasingly popular, but many people (this writer included) still find Outlook an indispensable part of the daily routine. One of the more common criticisms of Outlook is that it can run very slowly, and one of the reasons for this is that all its data is stored in a single file, generally called outlook.pst. When that file gets too large, performance can get sluggish.

Microsoft's partial solution to this is AutoArchive, which automatically moves older emails to a file called archive.pst (or a similar name). Information can be retrieved from this archive, but it takes longer. The process is based on the assumption that the older an email or appointment is, the less likely you are to want to retrieve it in a hurry.

AutoArchive is automatically switched on by default in Outlook, but won't automatically cover all of the folders where you sort your mail. In particular, it doesn't run on your main inbox. (The default AutoArchive settings move items into the archive if they're older than 6 months for calendar, tasks and journal entries, and 2 months for sent and deleted items.)

Depending on your work habits, the default backup periods might also be a nuisance. Tweaking your AutoArchive settings can help improve performance.

Note that if you're running Outlook on a work computer, your ability to change these settings may have been restricted. The steps below are based on Outlook 2007, but are similar in earlier versions of the product.

Where to find it


While there's an entry for AutoArchive under the Mail Cleanup option on the Tools menu, this doesn't let you change the settings. It simply runs AutoArchive automatically.

To adjust AutoArchive settings, go to Tools —> Options —> Other and click on the AutoArchive button. These are the main choices you'll be offered.

Run AutoArchive every x days The default setting of 14 days is fairly reasonable for most people. If this option is deselected, AutoArchive will only run if you manually choose it from the Tools menu. For most people, that's not a sensible choice.

Prompt before AutoArchive runs Once you're happy with your settings, it's often easier to switch this option off and avoid the annoying prompt that appears before the process begins. The main exception is if you regularly use a notebook and don't want archiving to be interrupted if you have to shut down in a hurry.

Delete expired items (e-mail folders only) For individual users, it's safe to leave this switched on, though it won't make much difference in practice.

Archive or delete old items You need this option selected for emails and other items to be moved into archive folders.

Show archive folder in folder list Tick this to have the archive folder appear in your folder list in Outlook, making it easier to check if you do want to see older emails. (The original folder structure will appear under an Archive Folders setting.)

Clean out items older than x months By default, this is set to six months; if you want a more extensive archive, try extending it to 12. If you receive a lot of email, a lower setting may be appropriate.

Move old items to This specifies the location of your archive file. Most backup software will assume the default location, so don't change it unless you have a very specific reason.

Permanently delete old items If you're super-confident that you won't need older emails or calendar entries, you can select this, but given the low cost of disk storage, that seems a foolish choice for most people.

Apply these settings to all folders now Clicking on this will set AutoArchive across your Outlook folders — a very useful way of ensuring that mail you've already sorted into folders does also eventually move into an archive.

If you want a more nuanced approach to archiving (perhaps there are folders you always want accessible), you can change the settings for individual folders. Right-click on a folder, select Properties, and then select the AutoArchive tab. From here, you can switch off archiving for that folder, or give it different settings to the default.

Even with AutoArchive set for maximum efficiency, there are plenty of other ways to speed up Outlook. If you want to move your Outlook settings from one computer to another, check out our comprehensive guide.

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    One thing in case anyone reading this doesn't know - the word 'backup' is used in this article, but I wouldn't refer to the AutoArchive feature as a backup.

    It doesn't make any duplicates of your files, and by default it stores the items in "%profilepath%\local settings\application data\microsoft\outlook\archive.pst" - which is generally on the same volume the outlook.pst file is located, so if your harddrive was to fail, you'd lose the email.

    Just pointing this out as the word 'backup' was used - when it isn't in fact a backup function at all. The emails get moved into the new pst file.

    Another thing to be mindful of is .pst files have a limit of 2gb. Once any .pst file gets bigger than 2gb it usually becomes corrupt - so if you have a lot of email, keep an eye on how big your pst files are getting.

      I recently changed computers and my .pst file is 6gb. The 2gb limit applies to old versions of outlook, but not 03 or 07.

        Cool, thanks for clarifying that. Makes me think there might be other issues that caused the corruptions in the instances I've seen (perhaps the file was originally created with office xp and kept the same format?)

        A bit of a followup:

        The reason for this is because Outlook 2002 files are, by default, in ANSI format and are limited to 2GB.

        Outlook 2003 and 2007, by default, create pst files in Unicode format, and their default maximum size is set at 20GB.

        That being said...I have seen large PST files (5gb+) cause problems on less powerful machines in Outlook 2003 and 2007.

    Here's what you need for proper backup :

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