Rollback mode
Discard everything written since boot when the machine powers off, so it returns to a known-good state every single time it starts.
Why it matters
Some machines should never accumulate state — a browsing VM, a malware sandbox, a demo environment, a machine you hand to someone else. Remembering to restore a snapshot after every session is the kind of discipline that fails quietly. Rollback mode makes it structural.
What changes
Without it
- You remember to restore a snapshot after each session, or you do not.
- State accumulates invisibly until the environment no longer matches the clean one you thought you had.
With 1VMTool
- Turn rollback mode on and the machine discards its writes at power-off.
- Every boot starts from the safe point, with no ritual to remember.
How it works
Pin a safe point
The machine records the clean state you want to return to.
Writes go to a scratch layer
The guest writes normally during the session; those writes are held apart from the safe point.
Power-off discards them
Shutting the machine down throws the session's writes away and leaves the safe point untouched.
What it covers
- Per-machine setting, not a global mode
- Clearly indicated in the machine detail view so it is never a surprise
- Combines with the snapshot tree — the safe point is a normal snapshot
What you get out of it
- A genuinely disposable environment with no cleanup step
- Safe to hand a machine to someone else
- Testing that starts from the same state every run
Try it on your own Mac
Every screen states its limits before you commit to anything.