I just checked, and the .nb files open correctly in Mathematica. You may have an anomaly peculiar to your system.
I did not check, but I am sure that the .m files will still want to open in Xcode if you double click the file icon.
On Nov 30, 2012, at 5:57 AM, James Stein <firstname.lastname@example.org> wrote:
> > I upgraded from v8 to v9 this morning, and all > pre-existing Mathematica Notebook files (extension .nb) have been modified > to open with the AppleScript editor. > > This is easily remedied by applying the "Get Info" command on one of the > notebooks; changing the "Open With:" item from "AppleScript Editor" to > "Mathematica", and clicking the "Change All" button to effect the change > for all notebook files --- but this has the nasty side effect of changing > the modification date of all your notebook files to the current date&time! > > This is unfortunate because notebooks in a given folder can no longer be > compared by age. > > I hope I made some error and this does not happen to others..... > > If others wish to do this, you might wish to do this on a folder-by-folder > basis: Select all the notebooks in a folder, press the option key along > with the command key and you will get a single Get Info window for all your > selected notebooks; this allows you to make the change for several > notebooks at a time, but not all notebooks on your computer. > > For those who have little or no use for the AppleScript editor, perhaps a > different solution is to replace the AppleScript Editor application with an > alias to the Mathematica application. I haven't tried this yet.... > > There may be utilities that allow you to change the "Open With" information > without changing the file dates. I haven't searched for them yet. > >