I backed mine up!!
Those who purchased Make The Cut prior to August 17, 2012 had the option to use a plugin to cut from Make The Cut to their Cricut machines. Those that downloaded before August 17th, 2012 it was the 4.1.0 version that you downloaded, so keep it safe.
Please note that the plugin for use with the Cricut machines
will NO LONGER work with versions of Make The Cut newer than 4.1.0.
If you have MTC 4.1.0, and are cutting to a Cricut, make a copy of MTC 4.1.0 and place in a safe place in case you ever need to reinstall it.
See the video tutorial by Scrappy Dew here to learn how to save multiple copies of Make The Cut to your computer: http://www.youtube.com/watch?v=V2f8Fbv27SQ
You will need to install any newer MTC versions to your computer in a different directory in order to retain your ability to design in the newer software and cut from the older software. When newer versions of Make The Cut come out, you can use the new version for designing. Select All, and Export your design as SVG, and import the SVG into your older version for cutting.
The new MTC version 4.1.1 was uploaded on August 18, 2012.
Info from Julie & Bryan on the MTC forum.