Could be that you have a formula that refers to another file.
Or, do you have a macro in there?

"Ryan" wrote:

I have a very simple three sheet Excel file which opens and saves OK.
However, typing in the sheet/cells is very slow. I thought the problem might
be associated with zooming but setting to 100% doesn't help. How can I track
down the source of this problem (it is isolated to one file)?