I have a rather large excel model run primarily by VBA and have been using it for the last 7 years or so with little problems. However, when I ran the macro today, the model doesn't update at all. Calculation is set to Automatic, and I can see that the macro is going through its normal process (which is visible in the status bar). At no point does the model timeout or show any runtime errors. The model worked perfectly on two days ago and the code hasn't changed at all since it last worked. So far, I have figured out a temporary fix for it, which is saving the workbook and reopening it and then rerunning the macro (works perfectly). The only thing I can think of is that I received a Security Update from Microsoft Windows yesterday. (I also deleted all of the .exd files that were causing problems on the Windows 12/12/14 update.) Has someone had similar issues?