The MRU option is stored in the Word (and Excel and Powerpoint)
registry "data" key.  This key can get corrupted and cause you
problem.

MS has a KB article (289634) which in part, gives the solution to your
problem:

Doug
====================================
Word Data Key in the Windows Registry:

Because most of the frequently used options (click Options on the
Tools menu) and some printer information are stored in the Data key,
one troubleshooting step is to delete the Data key. Word then rebuilds
this Data key by using the default settings the next time that Word is
started.

NOTE: Deleting the Data key resets several options back to the default
settings, including the "most recently used file list" on the File
menu and many settings that you customize in the Options dialog boxes.

WARNING: If you use Registry Editor incorrectly, you may cause serious
problems that may require you to reinstall your operating system.
Microsoft cannot guarantee that you can solve problems that result
from using Registry Editor incorrectly. Use Registry Editor at your
own risk.

To delete the Data key, follow these steps.
Quit all Microsoft Office programs.
Click Start, and then click Run.
In the Open box, type regedit, and then click OK.
Locate the following key in the Windows registry by expanding the
appropriate folders:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Word\Data
Click to select the Data folder.
On the Registry menu, click Export Registry File, type a file name,
and then click Save.
With the Data folder selected, click Delete on the Edit menu to delete
the Data key.
Click Yes to the following message:

Are you sure you want to delete this key?
On the File menu, click Exit to quit the Registry Editor.
Start Microsoft Word the way that you normally do. Do not use the /a
switch to start Word.
If Word starts correctly and functions correctly, you have resolved
the problem. The problem was a damaged Data key. You may need to
change a few settings to restore your favorite options in Microsoft
Word.

If the problem is not resolved, quit Microsoft Word and then add the
Data key information back to your Windows registry. To do this, locate
the Data key that you exported in step 6, and double-click it. Click
Yes to the following message:
Are you sure you want to add the information in C:\path\filename.reg
to the registry?

============================


  Diane Cummins <[log in to unmask]> wrote:
I only wish I could...that option is grayed out.  Is there another
'settings' group that would turn that option off?  I haven't been able
to find it.

Diane

Doug Simmons <[log in to unmask]> wrote:
In Office XP Word (and the other Office applications too), go to the
Menu "Tools", then Options. On the General tab, check the box for
"Recently used file list" and then choose how may files to retain in
the list (1-9). Do this for each of the Office applications and you
should be set.

Doug

At 7/24/2003 05:00 PM, Diane Cummins wrote:

Office XP was recently installed on my computer and my OS is Windows
2000. In each of the components--Word, Excel, Access--there is no
document history. ... When I go to View, Options, General (in Word),
the 'Recently used files' option is grayed out. That's true in Excel
and Access as well.

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