The ACAD environment variable is a system- or user-level variable that stores a semicolon-separated list of folder paths. AutoCAD reads these paths during startup reading the profile-specific support paths stored in the Windows Registry or the current workspace.
Each version needs its own support paths, drivers, and third-party plugins (ARX/DBX). If you point all versions to the same folder, you get a "FATAL ERROR: Unhandled Access Violation" because a 2025 ARX file will crash AutoCAD 2023. autodesk autocad --env.acad release name-
If you see the error message Autodesk AutoCAD $(env.ACADRELEASENAME) , it means the installer or update cannot find the base version of AutoCAD it's trying to modify. The ACAD environment variable is a system- or