The Folder trigger (v7.0+) executes the macro when a specified folder on your Mac:
The item must be directly in the folder - changes in a subfolder will not be noticed.
You can have the trigger ignore partial or changing files, so for example if a file is being downloaded or copied in to the folder, the trigger will wait until the download/copy has completed and can ignore partial files (files with extensions that are known to be “in progress” files).
Note that waiting for the file to stop changing adds a necessary delay to the trigger as Keyboard Maestro cannot tell in advance that the file has stopped changing.
The %TriggerValue% text token contains the path of the file that was added or removed (prior to 7.1 this was only the file name, not the full path).
See also these forum topics: