Photos: Re-import library to remove photos from "Master" folder?

Even if you create a new Photos Library, it should have an additional folder named "masters" in the subfolder resources/derivatives/masters . All of my Photos Libraries are having such folder. This folder contains downsized working copies of the unmodified originals. This folder cannot be avoided.

Or are you still seeing an additional folder "Masters" at the top level of the Photos Library? This would be an indication that your Photos Library is damaged and has never been completely upgraded. You wrote "I tried all the usual suggestions". I take it, you have already tried to repair the Photos Library? I would refrain from using third party apps, that are removing duplicate files directly from the Photos Library package, without using the Photos.app to do this. These tools may be causing more damage than good.

If your library is syncing with iCloud Photos, the easiest way to get rid of the old Masters folder would be to create a new, empty Photos Library and let this new library sync with iCloud Photos. This will recreate a new, pristine version of your library and download all media from iCloud with all albums, folders and metadata, like titles, keywords, etc. Only some of the named faces may be missing.

You might not save much storage by getting rid of the additional Master folder.

Usually duplicate photos in the Library do not need additional storage on an APFS file system, as the duplicates will be clones or hard links. If here are many cloned files in the Library, the size shown in the Finder may be way too large, because macOS is not computing the file size correctly, if there are clones and hard links. Occasionally my Photos Library has shown a size of twice the size of the internal drive of my Mac.

Perhaps the easiest, most efficient way to get your Library all cleaned up is to follow léonie's suggestion of relying on iCloud Photos to do the work. If you don't already, then you can get enough iCloud space (200GB for $3, or 2TB for $10) for a month, and let Photos copy your Library to iCloud and then let a new empty Photos Library get it all back together again.

The other easy and efficient method that might help is to use PowerPhotos to copy all the pictures from your Library to a new empty one. That costs $40 for the app, which is good for all sorts of additional things, and keeps you off iCloud, if that's important to you. PowerPhotos, like iCloud Photos, preserves all the organization and metadata.

I think either method would do the same thing. I would try the one that I already had the resource for, iCloud or PowerPhotos.

ou can use the paid version of PowerPhotos to merge older Photos libraries and iPhoto libraries into your current Photos library.

This comparison of Photos vs PowerPhotos merge features are shown in this user tip: Merging/Importing iPhoto/Photos library into Another Photos Library: PowerPhotos vs Photos.

PowerPhotos can check for duplicates durning the merge process if you'd like.

You can get the free version t verify that it can open each of your libraries before paying for the paid version.

It's not clear how your duplicates are avoiding the duplicate finders you've tried. The most robust and versatile duplicate finder that's usable within Photos is probably within the trusted 3rd party app PowerPhotos ($40.) You can also use PowerPhotos to make lists and sort by Kind or size on name or dimensions, which helps identify duplicates.

Are you saying that the duplicates are iPhoto versions that duplicate the Photos versions, or are there more kinds of duplicates? Are your problems with "exact" duplicates or with "similar" duplicates.

You can certainly export all the pictures from the Library, but which ones? The originals or the edited versions, or both? Any new stuff, like captions, titles, crops, enhancements, names, etc that you've added will only be available in the edited versions, but some information you may want later will have been edited out.

If you've used albums and folders to organize your Library, and if your pictures, like mine, take advantage of being in multiple albums, then all that will be lost in an export.

You can copy the "originals"folders from inside the Libraries, leaving the Libraries themselves untouched, and work with those outside the Library. Then you can import those to a new empty Library. Again, all the organization and edits will be lost.

I've restored old backups and gotten 10s and 20s of duplicates of some pictures. Since these were all original images, I worked with them outside of Photos. But, for me, removing pictures from the Photos system loses too much information.

I second the PowerPhotos suggestion. It is also the only app that I trust with the removal of duplicates, because it is essentially using Photos's interface to modify the library

léonie wrote: …I second the PowerPhotos suggestion. It is also the only app that I trust with the removal of duplicates, because it is essentially using Photos's interface to modify the library

PowerPhotos would also be way faster than iCloud. Say, 30 minutes compared to a week.

Also, if iCloud Photos runs into a corrupt file, it gets really complicated. I'm not sure what PowerPhotos does, but I bet it's faster at that, too, and it will give you more information about the problem.

The only problem would be, if the library damage is bad. PowerPhotos needs to be able to open the library in Photos to access the photos.