I'm working in Workbook A with no problems, everything works normally. I can
open any number of other workbooks and still not have any problems. In
particular, I can enter a line of data in a cell, alt-tab to another workbook
to get additional information, and come back to Wbkb A and continue entering
data in that cell with no problem.

But when I open one particular workbook (Wkbk B), the cell behavior in Wkbk
A changes. When I come back to Wkbk A and start typing I wipe out the
previous data instead of adding to it.

I do everthing exactly the same and have seen this behavior every week
without fail. The only thing that is different is that I've got Wkbk B open.
Wkbk B (along with C and D) are created each week by an export out of Crystal
Reports v11. C and D present no problems. Only B. What could it be about that
workbook that affects the cell behavior in Wkbk A?