Returnil creates a virtual system on your machine that completely mirrors your actual setup. It is designed to take the risk out of exposing your machine to all manner of software, websites, downloads, or anything else that might have adverse effects on your machine or infect it with malware.

Once restarted, your system will revert back to its original state and all changes to your primary partition will disappear. It’s free for home users. Don’t let this whole “virtualization” business put you off; aside from having a name that sounds like a pharmaceutical, Returnil is a very simple software to use that works really well.

You can think of it as a system-wide “undo” function; once you turn it on, you can do whatever you want with your system; all changes to your primary partition will be temporary and will disappear when you restart the computer.


Here’s how to use this software:

  1. Install Returnil: a very simple process. The only decision that is out of the ordinary is the option to create a virtual partition (the program will not need this partition, but you might; see point #4 below). During installation you can also set a master password to restrict access to the program.
  2. Turn Returnil’s protection on, when you need to; no actual changes will occur on your primary partition once this happens; from this point onward everything occurs on a “virtual” copy of your system.
  3. Do what you need to do: e.g. surf those dodgy internet sites, or install that piece of software that you want to test, or open the files you need to open, etc.
  4. Save your data: you will have to save any files you are working with someplace other than the primary partition (e.g. a secondary partition, a thumbdrive, or upload your files on the internet, etc.) Or let Returnil create a virtual partition for you; its purpose is precisely to provide a place for you to save your data when protection mode is turned on, and you can set any size you want for it that you have space for on your hard drive. Any files/data saved on the primary partition will eventually be lost.
  5. Restart the system: this is the only way ro turn Returnil’s protection off. Once this happens, any changes that happened when system protection was on will be gone; your system will look exactly the way it looked before you started.

returnilReturnil works by cloning your system settings in memory and implementing any changes virtually into that cloned entity. By working within memory it purports to offer better speed and reliability than other virtualization solution. If you are wondering, as I did, how Returnil can handle, say, an 80 gig primary partition within 128 or 512 megs of RAM, the answer to that question as stated in the FAQ section of their website is something to the effect that since the actual 80 gigs will remain unchanged, there is in fact no reason whatsoever to hold this entire disk image in memory. My understanding of this is that, in fact, all the program needs from your actual system is a bunch of settings that it uses to replicate your it within a constructed virtual environment. More notes on this program:

  • Making changes permanent: you cannot make changes made while in protection mode permanent even if you want to (unlike, say, Sandboxie). The only way to do this would be to re-do the changes normally with system protection off.
  • Testing software: while Returnil works extremely well for temporarily installing and testing programs within the virtual environment, programs that require a restart to install cannot be tested with Returnil as the restart switches off the virtual layer.
  • Deleting data: any deleted data or programs uninstalled while protection is on will actually be preserved and will re-appear when system protection is turned off and your machine is restarted.
  • The user interface: Returnil can be accessed through a system tray icon or a floating toolbar (see screenshot). You can use these to (a) turn system protection on, (b) mount/dismount the virtual drive, or (c) schedule system protection so it automatically turns on at specific times. You can also set a hotkey by which to activate system protection.

The verdict: as virtualization solutions go (see Altiris SVS and Sandboxie), Returnil is the simplest, most user friendly and intuitively comprehensible. As a user there are really only two things that you can do with this program; (a) turn system protection on, and (b) turn it off via a system restart. This not only makes Returnil extremely easy to use, but also contributes towards limiting any so-called ’leaking’ that sometimes occurs with virtualization programs where data meant for the virtual layer ’leaks’ into the actual system. This one is my favorite amongst all the free virtualization solutions mentioned above that I have come across so far. I highly recommend it. [Thanks go to reader Brockman for tipping me off about this program].

Version tested: Compatibility: Windows XP, 2003, VISTA 32 bit. Go to the program page to get the latest version (approx 1.7 megs).