Hi,

I have created a project management sheet. The user enters a few variables
on the overview worksheet, and using those variables Excel populates a
timeline and a cost estimate. As you can imagine, the sheet is full of
hundreds of formulas.

The sheet was created in Excel 2007, but I made sure that all the formulas I
used were compatible with Excel 2003, as that's what a lot of our users have.
Never the less, I have just saved the latest, and final version, and have
received the error:

File error: data may have been lost

Lots of my formulas are now empty (=N/A). The whole thing is broken.

I was supposed to present this to my boss in about two hours. I'm
reconstructing it now, painstakingly.

Can anyone tell me how to stop this error occuring in future?

Thanks

Karl