Applies to:
@RISK for Excel, all supported versions

Issue:
When running or ending a simulation in @RISK, you may encounter the error:

Automation Error: System Call Failed

Cause:
This error typically occurs when Excel 64-bit is unable to communicate with Microsoft Project. Certain @RISK operations or add-ins that integrate with Project may fail under 64-bit Office.

Workaround / Resolution:

1. Install 32-bit Office

   • The 32-bit version of Office provides full compatibility with @RISK and its integration with MS Project.

   • Ensure you uninstall any 64-bit Office installations before installing 32-bit Office.

2. Remove Outdated Office References

   • Previous Office installations can leave outdated registry keys that interfere with 32-bit Office.

   • Follow the steps in [Removing Outdated References to Office from the System Registry] to clean up these keys.

3. Reinstall or Repair

   • After cleaning the registry and installing 32-bit Office, repair your Office installation if needed.

   • Verify that Excel opens properly and @RISK add-ins load without error.

Additional Notes:

• This issue is specific to 64-bit Excel interacting with MS Project.

• Using 32-bit Office ensures proper communication between Excel, Project, and @RISK.

• Always back up your registry before making changes.