I opened some Excel files that I have been working on. All of these files
are pretty well established and the formulas have worked fine up until now.

When I tried to make a few changes this morning, none of the numbers would
update. After some searching around I discovered that my "Calculation" tab
had somehow changed to "Manual." I know I didn't change it and, even though
these worksheets are out on a project network at work, I don't think there's
any reason why anyone else would have changed it.

The problem has been resolved, but it is a little disturbing. Any idea how
or why something like this may have happened?