Files that contain the .metadata_never_index file extension are hidden files that have been created within an Apple device to prevent Spotlight (a built-in search tool on Apple computers) from indexing a file, folder or partition. For example, if there is a particular file, folder or partition on a user's hard drive that the user does not want Spotlight to index, the user must create a .metadata_never_index file to protect that information.
If the .metadata_never_index file is removed after it has been created, the information that the file was protecting from the Spotlight utility may then be indexed by the Spotlight program.
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