When
You need to edit footage on your PC.
Then
Choose a current desktop editor from its publisher's official distribution channel.
You can verify the source and check current requirements instead of trusting an old movie maker download from a mirror.
When
You are considering a browser-based tool.
Then
Review the service's identity, privacy information and terms before uploading footage.
Avoiding an installer changes the risk: sensitive video may leave your PC, and an online tool is not automatically safe.
When
You already have an unfamiliar installer.
Then
Pause before running it and perform the source, publisher and security checks.
An unknown file does not become trustworthy because its name contains movie maker.