Preference files are configuration files with an extension of .plist. They are present for both the local user and the operating system as a whole. These files store configurations for most, if not all, applications that operate within macOS.

Oftentimes, these files can become corrupted, thus causing unexpected problems with the operating system, application, or operation of the particular user account.

Removing the .plist file from the appropriate location and allowing for the OS or application to recreate it will mostly assist in these situations.

CAUTION: User or system configurations and/or settings may be lost as a result of modifying or deleting plist files.

See also: How to: Edit plist files in macOS