Has anyone had a similar problem: The latest (V7 in this case)
Mathematica installation seems to hijack the file association to .nb
files to itself. This is usually what the user wants, but in some cases
(if the latest version has severe bugs etc.) it would be nice to open
the notebooks with previous version (in V6 in this case) when
double-clicking in Explorer.
Usually one could just edit or remove the file association in
Tools->Folder Options->File Types with Windows Explorer, but Mathematica
seems to use some trick that always opens with the latest, even if you
try to change the association.
Has anybody found a workaround to this? The problem seems to exists at
least with XP and Vista.
When you set the file association to a particular Mathematica binary, add the
command-line option -directlaunch as the first argument to the binary. This
will disable the mechanism which launches the best available version of
User Interface Group
Wolfram Research, Inc.