For anyone who stambles on the error when running the simulations under new MacOS Catalina: "cannot be opened because the developer cannot be verified". You can follow the similar steps as here below for a walkaround. https://kb.tableau.com/articles/iss...ty-cannot-be-verified-on-macos-catalina-10-15 Copied steps from the link in case if the link becomes unavailable (it is about different library, but it doesn't matter, steps are the same): Grant permission to custactutil and custactutil_libFNP.dylib as follows: Click Cancel to dismiss the warning dialog. Note: Do not click Move to Trash. Open the Security & Privacy pane in System Preferences. At the bottom of the pane, the message "custactutil was blocked from use because it is not from an identified developer" is displayed. Click the Allow Anyway button. Run custactutil again. The warning message is displayed for a second time, but now an Open button displays. Click Open. The warning message displays for a third time, this time referencing custactutil_libFNP.dylib and offering options to Move to Trash or Cancel. Click Cancel. Go back to the Security & Privacy pane and click Allow Anyway for this library file. Run custactutil again. The warning message will be displayed for a fourth time. click the Open button. EDIT: Some other good solutions are listed here: https://github.com/hashicorp/terraform/issues/23033#issuecomment-542302933