I've made three snapshots on VirtualBox virtual machine (Windows XP).
I want to go back to Snapshot 2.
Simply click on the snapshot you want to go back to, then click the "Restore" icon:
Note that your current state will be discarded when you restore a snapshot.
All further snapshots from the restored one will be conserved and you will simply start a new branch of snapshots starting from the restored one.
I know I'm a little late to answer this question, but maybe you'll still find these thoughts helpful.
As of today (4/30/10), the current version of VirtualBox allows you to revert to any snapshot WITHOUT having to delete child snapshots.
For instance, grrussell suggested that you have to delete snapshot 3 in order to return to snapshot 2. I don't know if this was the case in earlier versions of VirtualBox, but the most current version does not require this.
You can revert to snapshot 2 and make changes, and then either save a new snapshot (which would be a sibling of snapshot 3) or discard your changes and revert to snapshot 3 (or the "base" snapshot, if you so desire).
The first answer is incorrect. You can restore ANY snapshot, but it will replace your CURRENT STATE with the new snapshot.
In the example above, if you restore Snapshot 2, it will now become your current snapshot so you've essentially created a branch of Snapshot 2 and Snapshot 3 is a different branch of Snapshot of 2 which is now frozen in time unless you restore Snapshot 3 at some point in the future.
As of current version 7.0 this setting is changed.
The text reads:
“You are about to restore snapshot before-Switching-Desktop-Env.
You can create a snapshot of the current state of the virtual machine first by checking the box below; if you do not do this the current state will be permanently lost. Do you wish to proceed?”
Afaict, you have to discard the snapshot 3 to return to snapshot 2. See section 3.4.4 of the User manual, downloadable in PDF.
Quote:
To revert to an earlier snapshot, you right-click on the “Current state” item and select “Revert to current snapshot”. This will bring the VM back to the state of the nearest (most recent) snapshot. Similarly, you can merge several earlier snapshots into one by right-clicking on a snapshot and selecting “Discard snapshot”.
Note: The snapshot reverted to will affect the virtual hard drives that are connected to your VM, as the entire state of the virtual hard drive will be reverted as well. This means also that all files that have been created since the snapshot and all other file changes will be lost. In order to prevent such data loss while still making use of the snapshot feature, it is possible to add a second hard drive in “write-through” mode using the VBoxManage interface and use it to store your data. As write-through hard drives are not included in snapshots, they remain unaltered when a machine is reverted. See chapter 5.3, Configuring image write operations, page 78 for details
