I have had a group of users who have raised an issue with Office 2013 running far slower for a number of spreadsheets. After investigating the fault, I have identified the issue as being due to the way in which Excel appears to be handling the calculations. When I open the spreadsheet myself, on Office 2013 32 or 64 bit, I am asked to update the data, at which point the spreadsheet runs the calculations if I accept, and then runs them again. If I set this behaviour to manual, I can open the spreadsheet, request an update, and then manually calculate, which only takes one pass at the data but provides the same results. The behaviour does not persist on an Excel 2010 machine, which does only a single pass on both manual and automatic. The spreadsheet does pull data from an external sheet, but as this only occurs in Office 2013, I don't believe this to be intended behaviour.
Is there anyone who can shed some insight into why this acts this way, and how to prevent this. We are trying to upgrade our business to 2013, and are getting a huge amount of push back from this particular set of users over this issue