Installing H&R Block software

The first thing that you check with new software is its compatibility with the current operating system that is in use. That can be checked at the vendor's site and their system requirements. If in fact, you are still running El Capitan, you may find that some software vendors have changed their minimum macOS version requirements from five-year old operating systems.

Talk to Block's tech support. The software is not an Apple product.

Please read Writing an effective Apple Support Communities question. We are here to help. We are all users. We are not mind-readers nor clairvoyants. We only know what you write down and tell us. Be specific and thorough. Include your hardware information and installed version of macOS.

FYI: These are user-only forums. You are not speaking to Apple. if you need to speak with Apple Support, then contact product and tech support:  Contacting Apple for support and service including international calling numbers.

Thank you for your understanding and support.