Changing how AutoArchive works
There are two sets of AutoArchive settings: global settings and per-folder settings. The global settings “called default settings” determine whether AutoArchive runs at all and what it does by default with the items in any Outlook folder (except Contacts, which is not affected by AutoArchive). The per-folder settings override the default settings so you can AutoArchive individual folders differently. If you don’t specify AutoArchive settings for a specific folder, the folder will not be archived. Default settings and per-folder settings apply to the current mailbox only. If you want, you can also manually archive items.

Changing the default AutoArchive settings in Outlook:

On the Tools menu, click Options

Click the Other tab, then Click AutoArchive

With Run AutoArchive every numbered days selected, specify how often to run AutoArchive.

Select the options that you want.

To apply the changes to all folders, click Apply these settings to all folders now. This will override custom archive settings that you’ve specified on individual folders.

Click OK.

How to specify AutoArchive settings for individual folders:

Click Folder List

Right-click the folder you want to specify settings for, and then click Properties on the shortcut menu.

Click the AutoArchive tab.

Specify whether you want to archive this folder and if so, whether to use the default AutoArchive settings or your own settings.

To archive to a file other than the default one, specify a different file name in the Move old items to box. The next time AutoArchive runs on this folder, Outlook will automatically create the new archive file for items in this folder.

Click OK.