If you need a true sandbox (e.g., for running two different Unity versions that conflict, or for use on locked-down corporate PCs where you cannot write any files to C:), application virtualization is the "top" technical answer.

This method involves a two-step process. First, use the Download Assistant on an online computer to download all necessary installation files. Second, copy those files along with a generated installation script to any other computer for installation.

: Write a PowerShell script that runs when you plug in your drive. It can check for necessary dependencies, set environment variables, and launch your native hub.

If you're setting this up for a specific project like Android development, make sure to install the Android Build Support

Unity Portable Install is a self-contained version of the Unity engine that can be installed on a portable device, such as a USB drive or external hard drive. This allows you to carry your Unity installation with you, and use it on any computer without the need for administrative privileges or installation.

: Some cloud services allow you to work on Unity projects remotely. For example, you can use Google Stadia, AWS, or Microsoft Azure for cloud-based game development. This approach doesn't require installing Unity on your local machine.

To prepare a portable Unity installation, you essentially create a standalone folder containing the Unity Editor and your project files that can be run from a USB flash drive or external drive without a traditional installation process. While Unity does not officially offer a "portable" edition, you can manually set one up following these steps:

: Launch the Download Assistant. On the "Choose Download and Install locations" screen, select the "Download to" radio button. This crucial step instructs the Assistant to download all components to a specified folder rather than performing a standard system install.