An efficient
way to reduce the size of your Outlook Data File (.pst) or Exchange mailbox is
to regularly archive older items. Unlike a traditional backup in which a copy of
Outlook items is made, archived items are moved to a separate Outlook Data File
(.pst). Archived items can be accessed at any time by opening the file.

By default, older Outlook items archived automatically on a regular interval.
To learn more about AutoArchive, see Use
AutoArchive to back up or delete items .
You can also manually back up and archive items, in addition to AutoArchive
or as a replacement. Manual archiving provides flexibility, and allows you to
specify exactly which folders are included in the archive, and which archive
Outlook Data File (.pst) is used.
To manually archive Outlook items, do the following:

1. Click the File tab
2. Click Cleanup Tools.
3. Click Archive.
4. Click the Archive this folder and all subfolders option, and
   then click the folder that you want to archive. Any subfolder of the folder you
   select is included in this manual archive.
5. Under Archive items older than, enter a date.

1. If you do not want to use the default file or location, under Archive file, click Browse to specify a new file or
   location. Browse to find the file that you want, or enter the file name, then
   click OK. The destination file location appears in the Archive file box.
2. Select the Include items with “Do not AutoArchive” checked
   check box to include any items that might be individually marked to be excluded
   from automatic archiving. This option does not remove that exclusion from these
   items, but instead ignores the Do not AutoArchive check box for
   this archive only.

Turn off AutoArchive

If you want to archive only manually, you must turn off AutoArchive. Do the
following:

1. Click the File tab.
2. Click Options.
3. On the Advanced tab, under AutoArchive,
   click AutoArchive Settings.
4. Clear the Run AutoArchive every n days check box.