Microsoft announced it has stopped supporting Movie Maker and Photo Gallery (part of Windows Essentials 2012) as of January 10, 2017.
Here are a few questions and answers:
Are the programs still available for download?
The web installers and offline installers that used to be available at download.live.com have all been removed. The following response to a question on Microsoft Answers might help:
Where to get a Safe Download of Movie Maker
Where are the Windows Essentials Offline Installers for other languages?
They have all been removed from the Microsoft website.
What happens to Movie Maker (and Photo Gallery) if it is already installed?
Already installed applications will continue to work as they do today but there will be no updates.
What are the recommended alternatives for Movie Maker and Photo Gallery from Microsoft?
As part of the Fall Creators Update to Windows 10, the Photos App now includes the ability to create a movie from your photos and videos. You can either let it start the process using the Create > Video remix option, or you can do it yourself using the Create > Video project.
What other options are there?
ProVideoCoalition has posted their Free Video Editing Software Guide for 2017.