Before setting up a portable install of Autodesk Fusion 360, ensure that your system meets the following requirements:
If you truly need CAD portability without installing anything on host computers, abandon the "portable install" dream and consider a autodesk+fusion+360+portable+install
You still need to install Fusion on the OS you are using, but you can direct the cache and project files to an external drive to keep your internal disk clean. Before setting up a portable install of Autodesk
Fusion 360 uses a "streaming" installer. This means the initial download is small, and the rest of the data downloads in the background while you work. autodesk+fusion+360+portable+install