Currently TaxCalc is partially supported on the Catalina operating system (which was released in October 2019) as per our System Requirements for TaxCalc.
If your Mac has been updated to Catalina, you can try to use TaxCalc but it is worth noting that this has not been tested and may have some unusual behaviour. We are limited on the support that we can provide you with at this stage. This being said, many customers have reported that they have been able to get this running by following the below help instructions.
When attempting to open TaxCalc, you may be prompted with “TaxCalcHub” can’t be opened because Apple cannot check it for malicious software (as shown below).
Mac OS 'Catalina' contains a new security feature that prevents app that have not been notarized from being run without users taking exceptional steps. For more information on how to resolve this please see Apple's help here. The section within this article you will require is under the heading for How to open an app that hasn’t been notarized or is from an unidentified developer.
For your records, a case has been raised with our team (under reference PROD-2708) which will track our notization process. Once we have this in place, you should no longer receive the prompt above.