Notes on Migrating an Aperture Library from Aperture to Photos for Mac - 2019 version

by: léonie

Last modified: Jan 20, 2022 11:20 PM

6 6648 Last modified Jan 20, 2022 11:20 PM

You will have seen the announcement - Aperture will no longer run on any system past macOS 10.14 Mojave. See: Migrate your Aperture libraries to Photos or Adobe Lightroom Classic - Apple Support

Apple recommends migrate your Aperture Libraries either to Lightroom Classic or to Photos.

There are several professional photos managers, that could replace Aperture, but Lightroom Classic offers a migration tool for an easy conversion of the library.

Photos is by no means a replacement for Aperture, if you need a full fledged professional application. But the migration to Photos can ensure you the access to your Aperture Libraries after the upgrade to the successor system of Mojave, and the migration will be nearly lossless, keeping the originale and edited versions paired, and Saving the albums and most of the metadata.

More benefits of migrating to Photos: Photos is the first native Apple application, that lets you store a photo library in iCloud and sync it across all devices. It is a successor to iPhoto, and its editing tools are now more versatile than they have been in iPhoto (in Photos 4.0). The support for metadata and projects like Books or slideshow ist still very limited. (Welcome to Photos - Apple Support)(Get started with Photos for OS X - Apple Support)

While the new Photos application has not much to offer for professional users accustomed to Aperture's tools to manage a large library and customize the tools and metadata presets for an efficient workflow, you may want to upload a subset of your photos to iCloud for easy access on all devices. To do that, export selected albums and project from your main Aperture library as a new Aperture library with "File > Export > xxx as new library".

How to prepare for the migration: Precautions to take

The migration of the partial Aperture library to Photos will be smoother, if you take a few precautions.

Get the Aperture Library ship-shape

Backup: First of all, as always, when upgrading the system, make a full backup, so you can revert to the previous state. Make a Time Machine backup or a bootable clone.
Upgrade older libraries to Aperture 3.6: Open the Library in the current version of Aperture to upgrade it to Aperture 3.6. When I tested to migrate older libraries, Photos 4.0 crashed, if I did not open the library first in Aperture 3.6. Ensure that your Aperture Library has no issues before the migration. Repair the permissions, and repair the database. (Repairing and Rebuilding Your Aperture Library: Aperture 3 User Manual)
Merge Libraries: Photos has no tool to merge libraries. You can only merge libraries lossy - by exporting or reimporting. For a lossless merge you need to upload them to iCloud Photos. If you want to merge your libraries, do it now, while you still have the power of Aperture. (Aperture 3.3: How to use Aperture to merge iPhoto libraries). See also: Notes on Merging Photos Libraries | Apple Support Communities
Relocate or consolidate any referenced files: Photos has a very limited support for referenced files. But photos with referenced originals cannot be used with iCloud Photo Library. If your Aperture libraries are referenced, do any relocation and reconnection now. Photos cannot relocate originals, and has no versatile tool for reconnecting missing originals. Photos has no tool to reconnect referenced originals like Aperture has. If an original is missing, you have to find it without a reconnect window like Aperture had. You can consolidate originals, but not relocate them.
Remove and convert incompatible media: An Aperture library can contain media files, for example audio files or videos with codecs, that Photos cannot handle. Some color profiles will also cause problems. These items can cause Photos to hang or crash later. Before you migrate the Aperture Library, check for media types, that are not supported by Photos and convert them to a compatible format. This list (for iMovie) will give you an idea, which file formats will be supported in the long run by MacOS X: About incompatible media in iMovie for macOS - Apple Support

Add the final touches to the metadata:

Photos does not have the elaborate batch changing tools that Aperture has. And we cannot write metadata to the originals. If you want to tag your originals, do it now.

Batch change titles and descriptions: if you need to batch change titles or captions, do it in Aperture, while you can.
Hierarchical keywords: Photos does not support hierarchical keywords, so flatten the keywords structure, while you can still use Aperture's Keywords HUD.
Geocoding: If you have photos in your Aperture Library, that do not yet have GPS locations assigned, add the locations while your library is still in Aperture. Photos allows you to assign a location by dropping a pin on a tiny map or entering a location name. With much fiddling you can assign places this way. But you cannot copy and stamp the locations. Photos will copy the location name, not the GPS coordinates, so the pasted location may be inaccurate. The first version of Photos (version 1.0) neither supported geotagging nor batch changing.. Version 1.1 makes it possible to assign locations, but only on coarse maps without much detail. Version 2.0 has more detailed maps, but these better maps are not available, when assigning places.
Custom metadata: Save your custom metadata tags to the captions field or wherever you can see them in Photos. The custom metadata will not be migrated.
Projects: Photos does not have projects, but structures the library by Moments and Collections, which are created automatically, based on the locations and capture dates. The moments will roughly correspond to shooting sessions - all photos taken at the same time at the same location. It is important to check the dates and locations for consistency, before you migrate. Later it might be difficult to correct them. The projects will be migrated as albums. Since Photos does not have projects like Aperture, smart albums based on projects will not be transferred to Photos.
Named People: The named people migrated well, when I tested in Photos 4.0, but it may be safer, to assign the names as keywords to the named people. Photos uses a different face recognition algorithm and occasionally people albums get merged. The keywords will help to separate them again.

The location of the library

If your Aperture Library is not in your Pictures folder, but on an external drive, check the drive for compatibility. Photos may have problems accessing the drive, if it is on a network volume and not locally mounted. If you are planning to use the library with iCloud Photo Library, the drive must be formatted MacOS Extended (Journaled) or APFS. And I strongly recommend to use only MacOS Extended (Journaled) or APFS volumes anyway. Move your Aperture Library to a correctly formatted locally mounted volume, if necessary. Even, if you are not planning to use iCloud, Photos may not be able to to migrate the library, if the file system is not compatible. Photos can open a library on drives with a different file system format, but during the migration it needs to create hard links, and the file system must support hard links or the migrated library will be created on the system drive. See: Where is it safe to store a Photos Library? Requirements for the external drive

In short, the file system format should be (Move your Photos library to save space on your Mac - Apple Support)

MacOS Extended (journaled) or APFS
not case-sensitive
The volume must not have been used by Time Machine
The volume must be locally mounted and not a synced volume (iCloud Drive, Google Drive, dropbox or similar)

How Photos handles the Migration:

Your new Photos library will be created in the same folder as your original Aperture Library. Make sure, you have free storage in that location. Photos will not duplicate your original image files from the Aperture Library, but link to these files with hard links to save space: https://web.archive.org/web/20190502225116/https://support.apple.com/en-us/HT204476 (old broken link: Photos saves disk space by sharing images with your iPhoto or Aperture libraries - Apple Support)

See here, what will migrate and what not:

Don't delete your old Aperture Library in a hurry. It does not need much space, and you may need to revert to it, if the migration will not succeed. Photos will need additional storage during the migration that will be released later. Photos will migrate the last Aperture Library you opened before the migration automatically. So switch to the library you want to migrate, before you open Photos for the first time.

This User Tip by Old Toad lists the differences between iPhoto and Photos as a check list. It can help you decide, if you should migrate to Photos or not: Photos vs iPhoto: Features and Capabilities

As you can see, even basic iPhoto features are not yet supported in Photos. None of the Aperture features, that are not mentioned in the table are supported in Photos - brushed adjustments, saved presets, relocating managed originals as referenced originals, custom metadata tags, hierarchical keywords.

Good luck for your migration of selected Aperture Libraries to Photos.

Here is a list of more user tips for Photos: Thematic Index to Photos for Mac related … - Apple Community

(old version: Notes on Migrating an Aperture Library from Aperture to Photos for Mac)