To begin finding duplicate photos in your Photos libraries, either click the magnifying glass button in the toolbar, or select “Find Duplicates” from the Library menu. This will present you with a view to set up your duplicate finding.
There are two areas you need to set up to begin your duplicate search
What to search The Find Duplicates command can search one or more Photos libraries at once, looking for duplicate photos. To search a library, drag it from the library list on the left into the area labelled “Choose Libraries to Search”. To remove a library, click the X next to its name.
You also have the option to exclude certain photos from being included in the search. Click the “Exclusions…” button, and you will be given the option to skip looking at photos that are already in the “PowerPhotos duplicate trash” album (e.g. if you performed a previous duplicate search already), or are marked as hidden.
How to compare photos PowerPhotos has two methods that you can use to compare photos to each other and determine whether they are duplicates. Refer to the duplicate comparison options chapter for details on how these work.
Once you’ve set up your search, click the blue “Begin Duplicate Search” button in the upper right corner of the window, and PowerPhotos will begin analyzing your libraries for duplicate photos.