Taking a snapshot in VMware Fusion lets you preserve the state of the virtual machine so that you can return to that state.

You might take a snapshot any time you are about to take an action in your virtual machine and you are unsure of the consequences. For example, you might take a snapshot before you make a change to your virtual machine's system software, such as an operating system upgrade or a major configuration change. If something doesn't work as expected after the change, you can restore the snapshot to return the virtual machine to its previous state.

You might also take a snapshot before you go on to the Internet, or log in to an unknown network. If your computer acquires a software virus or spyware, you can restore the snapshot to return the virtual machine to its previous uninfected state.

A snapshot captures the entire state of the virtual machine at the time you take the snapshot.

Memory state – Contents of the virtual machine memory

Settings state – Virtual machine settings

Disk state – State of all the virtual disks

A snapshot is not the same as a backup. It is not a copy of your virtual machine.