As I understand it, a sandbox is an isolated environment on a machine, used to gather informations on a threat, or test it directly. That's made so that the threat can't harm anything, once you're done you delete that isolated environment, most likely a virtual machine and you're safe.
The main goal is, you're isolated so you're not at risk for what you have outside of the sandbox.
I wondered if there's something similar to the sandbox (like a hardened environment with testing tools inside) to test safely what happens on your computer (which is absolutely not safe, and which you absolutely can't afford to reset) from your own computer ? Like I don't know, some kind of partition that is barely accessible from the main working environment, that couldn't be infected easily, and which you could use to troubleshoot what's happening on your main user session whenever something wrong happens ?
If something like that exists, how is that called ?