Formula recalc question

[drzimmerman]

Someone has sent me a spreadsheet (as an email attachment) where a simple sum formula has not been recalculated, as when I open the email from Outlook, it opens in Excel 2010 in protected view and I can see the cell value is wrong.

However when I enable editing, the formula is recalculated and the correct cell value shown. My question is - how have they managed to send me an email attachment with the formula not recalculated, but it recalcs when I open it? If they had manual recalculation set in the spreadsheet when they sent it, shouldnt it still be manual when I open it and not recalc?

Any thoughts?

thanks very much

Zimmerman