Do not install HYSYS on a mechanical HDD (Hard Disk Drive). The SOLVER engine uses thousands of temporary iterative files. On an HDD, a simulation that converges in 10 seconds will take 4 minutes.
Below is a breakdown for (current version as of 2025). Aspen Hysys System Requirements
Office 2016, 2019, or 365 (32-bit Visio is specifically required for some legacy features). Database: Do not install HYSYS on a mechanical HDD (Hard Disk Drive)