Applies to: @RISK, all releases

Why do errors appear in outputs when Multiple CPU is enabled?

When Multiple CPU is enabled, each worker CPU runs a private copy of your workbook. Workers do not share data between themselves or with the master until values are returned. This means any outputs depending on data from other iterations, statistics of @RISK outputs, or macros that store values in the workbook may show errors during those iterations.

Solutions:

• Disable Multiple CPU: This ensures all iterations use the same workbook and avoids missing data.

• Use theoretical functions: For statistics referencing @RISK distributions, replace functions like RiskMean with RiskTheoMean or RiskPtoX with RiskTheoPtoX.

• Macro adjustments: Macros writing to the workbook during worker CPU iterations will not persist. Consider writing to external files with care for simultaneous access.

Important: The @RISK XDK object model is unavailable on worker CPUs. Any automation requiring XDK must run with Multiple CPU disabled.