
Michael H. answered 01/23/20
High School Math, Physics, Computer Science & SAT/GRE/AP/PRAXIS Prep
You likely do not have the required software. Do a Google search for "7z", "unrar", and/or "xz". Install those archival programs and try again. I recommend that you do this in Linux, not Windows or Apple.
It is also possible, but unlikely, that the file is corrupted so badly that it cannot be recognized by the archival program that you are using.