I'm not in front of Excel 2010, but does the same issue occur when your formulae are on a different worksheet?
So if Monarch exports to Sheet1, and on Sheet 2 you have references to !Sheet1$A1, can Monarch still update Sheet1 OK and does Sheet2 still refresh?
My hunch is that it's to do with named ranges getting corrupted in Excel, so Monarch can find the place it thinks the project export should go to.
Hope that helps,
if the formulas are moved to another worksheet then the project export runs perfectly so there is definitely an issue with the worksheet sharing the export in columns A to E with formulas in column F. Funny thing is that if you try to export in Monarch 7 (which we recently upgraded from) then the export runs perfectly. We are now running via Monarch 11 and Excel 2010 so perhaps this application combination is causing the issue somehow?