HomeTechniques and TipsAll ProductsUsing Excel During Simulation or Optimization

1.6. Using Excel During Simulation or Optimization

Applies to:
@RISK for Excel 5.x–7.x
RISKOptimizer 5.x (6.x and newer are part of @RISK)
Evolver 5.x–7.x

My simulation or optimization takes some time to run.  During that time, I would like to work on another workbook.  Is there any way I can use Excel for something else during a simulation or optimization?

Yes, you can open a second instance of Excel and do anything in that instance, with one exception: Don't run a Palisade product in that second instance of Excel.  (If you want to work on a workbook that contains @RISK functions, they will all appear in the cells as #NAME.  However, you can edit the formulas in the formula bar, copy/paste formulas, and so on.)

Opening a second instance of Excel is not the same thing as opening a second workbook in Excel. If you open a second workbook, the existing copy of Excel opens it, so you have one copy of Excel running and there's one Excel line in Task Manager. You can have multiple workbooks open when running our software, but don't switch workbooks while a simulation or other analysis is running. By contrast, when you open a second instance, Windows loads a fresh second copy of Excel, and Task Manager shows two Excel lines. Our software will fail with "Object initialized twice" or another message if you try to open it in a second instance of Excel.

Confusingly, Excel 2013 and 2016 look like second instances when you simply open a second workbook. They show multiple taskbar icons, usually stacked, and the Windows actions to switch to a different program will switch between those workbooks, even though they're open in the same program. The only way to be sure is to look at Task Manager to determine whether there's one line for Excel, or more than one.

Only these specific actions will open a second instance of Excel:

Important: Don't attempt to run any Palisade software in that second instance of Excel.

Last edited: 2017-11-16

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