Manual calculation not working

Originally Posted by EMAC

I often work with financial models in Excel with circular references using manual calculation. Everything usually works fine but from time to time, some cells stop updating when I hit F9. The problem cells will calculate if I select them and hit F2 then enter (one cell at a time). Any idea why this is happening and how to fix or avoid it?

Following link may help you understand the way Excel calculates.

http://www.decisionmodels.com/calcsecretsg.htm