With virtual machines, it is possible to run Tails inside a *host* operating system. A virtual machine emulates a real computer and its operating system, called a *guest*, which appears in a window on the *host* operating system.
<p>For example, when using virtual machines in Windows, <a href="https://support.microsoft.com/en-us/windows/retrace-your-steps-with-recall-aa03f8a0-a78b-4b3e-b0a1-2eb8ac48701c"><i>Microsoft Recall</i></a> might be taking regular screenshots of your activity.</p>
<p>We only mention Free Software, because we believe that it is a necessary condition to be trustworthy. Proprietary virtualization software exist, such as <i>VMWare</i>, but is not listed here on purpose.</p>