If you would like to change Outlook 2010’s default attachment location, follow the instructions below:
To change Outlook 2010’s default “insert attachment” folder
1- Open Word 2010 (not Outlook!)
2- In Word 2010, go to the “File” tab (left of the “Home” tab). Click “Option” (near bottom of left hand list).
3- In “Word Options” pop-up window, find “Save” (middle of left hand list)
4- Look for “Default file location:” and browse to whichever folder you wish.
5- Click OK.
6- Back to Outlook: close and re-open Outlook 2010, and the default folder will be changed.