How to Weed out Legacy Media in Photos for Mac

Written for Photos 5 on Catalina

The Problem of Legacy Media in Photos

Photos for Mac does not support all media formats, that have been compatible with Aperture or iPhoto.

We will notice this, when we try to import items into a Photos Library and get an alert about incompatible Media or the items are dimmed in the Import panel, for example: If you can't play videos in Photos on your Mac - Apple Support)

When we create a new Photos Library, it will be unlikely, that there are incompatible legacy items in the library, as we will be warned, when we import new items. But such legacy media could have been migrated to Photos and will be dormant landmines, if we open existing Aperture Libraries or iPhoto Libraries in Photos for Mac. Photos cannot process these items and may crash or hang, when we try to edit these items, when the background processes try to create thumbnails and previews, or the item may block the syncing with iCloud. We have to find and to remove them.

The recent upgrade to macOS Catalina made additional items incompatible, especially older video formats and PDFs can no longer be used in a Photos Library. Apple did not release a list of legacy items for Photos, but we can use the list for iMovie as a guideline, see: https://web.archive.org/web/20240123090939/https://support.apple.com/en-us/102232

(this document has been removed:  About legacy media in iMovie for macOS - Apple Support)

We need to remove all audio files from the library (they may have been added to an Aperture Library as sound tracks for slideshows), PDFs can currently not be imported, older image formats like PICT, BMP, mp3 videos. When in doubt, if an item is compatible with Photos, export the unmodified original from the library, then try to import it to a new test library. If Photos can import it, it is safe. Any item, that has not been taken with a camera, but downloaded from the web, saved from a Mail, created by a graphics program or scanned photos are suspects for legacy media formats.Even JPEGs could have incompatible color sync profiles embedded.

How to screen the library systematically for Legacy Media

Are there any items in your library, that have been added many years ago? Old videos, that are not in the HEVC or H.264 format? Are there any audio files in the library that you have used for slideshows? Or PDF files? Does your library contain referenced image files? Photos that are stored and referenced outside the library and are not imported into the library are currently causing the iCloud upload to hang in Photos 5 on Catalina.

.To search systematically for problematic items, smart albums can help.

I have been using two different smart albums.

• The first album, named needs_checking, is excluding all photos and videos that are definitely compatible. The remaining items need checking. Create the album with "File > New Smart Album". Set the rules to "Filename does not end with JPEG", "Filename does not end with JPG","Filename does not end with HEIC", etc, and combine the rules with "Match All". Look at the remaining item and check the filename extensions, to see the formats of the items
• The second smart album is looking directly for photos of a certain media format, that need covering to a different format. You may have to add the formats that your external editors are creating to the list.

The rule "Unable to upload to iCloud Photos" will show items, that Photos has identified as incompatible. The rule "Photo is referenced" is looking for items stored outside the library and referenced by photos. Modify this list freely according to the filetypes in your library.

When you find suspicious items export them from the library as unmodified original, then delete the item from the library and convert the exported file to a more compatible format. On Catalina you may need third party editors to do the conversion.