If you have installed MV via steam, you can safely delete the entire NewData folder, and then have steam verify that all the files for the software are downloaded properly. This will fail on the NewData folder because it will be missing. Steam will then redownload a clean copy of that folder to your installation, effectively resetting it back to a clean state.
In order to verify that all files for an installation are ok with steam, go to your steam library, locate the game or software you want to check, right click it, and select properties. A new window will open up. In this new window, select the "Local Files" tab, and hen the 3rd or so button down will be "Verify the integrity of the application cache", or similar wording. Press this button, and steam will check the installation to ensure nothing is corrupt, and it will automatically redownload anything that it deems is in a bad state.
If you don't have MV installed through steam, your only option is probably to uninstall and reinstall MV in order for the installer to restore the default folder.