Does anybody know why these two Excel files must be open in the sameprocess?

Hi all,

I am doing the following sequence of operations all the time:

1. Open up an Excel 2003 sheet A;
2. Click a button and run a macro in that Excel sheet;
3. After it finishes running, open up another Excel 2003 sheet B in
the same Excel session/process;
4. Press F9 to do calculation/update the sheet, and save the Sheet B.

B has a lot links linked to A...
-----------------

Sometimes, if I update file A, save it, and close it before opening B,
(i.e. now the file B and A are not in the same Excel session/
process) , B's update will fail (i.e. B's links will not get updated,
and numbers not refreshed...)

Anybody knows why?

Thanks!