After adjusting your toolbars as you like them, you may discover that
Outlook doesn't remember their position the next time you open it. This is
most often caused by add-ins that set a specific position for their toolbar
or don't properly handle toolbars.
Add-ins known to cause problems include:
Business Contact Manager (BCM)
Adobe Acrobat Outlook add-in
Outlook does not have a "lock toolbar" feature at this time, leaving your
only choices to disabling the toolbar that is causing them to move or using
the default toolbar layout.
More Information
Outlook stores toolbar information in a file called outcmd.dat. You
can delete or rename this file to reset your toolbars to the default
configuration and Outlook will recreate it. If you haven't
customized any toolbars, outcmd.dat won't exist. (In Windows XP or
Windows 2000, it's located at C:\Documents and
Settings\username\Application Data\Microsoft\Outlook.)
Word
Editor:
The toolbars shown when you compose a new message using Microsoft
Word as the editor are stored in Word's normal.dot template. If you
change a setting or display a toolbar while using Word, that setting
or toolbar will be visible when composing new email too.