Isaac from Balaclava wrote:
"Legacy Media"??? What do you mean
When Apple made the transition from 32-bit to 64-bit final with the upgrade from macOS 10.14 Mojave to macOS 10.15 Catalina, the support for some older media formats from the iLife packages has been removed from the system and Phots can no longer process these older formats after upgrading to a 64-bit only system version. if we did not weed out all media, that can no longer be processed before upgrading to Catalina, we now may be having files in our Photos Library, that can no longer be processed, and may be blocking the background processes for the face recognition and object recognition. I have never found a list of problematic items for Photos, but used the list for iMovie as a guide: About legacy media in iMovie for macOS - Apple Support
i tested all videos by exporting the unmodified originals and then tried to import them in small groups into a new, empty Photos Library. Then I converted all videos that have been shown incompatible to HEVC on my Mac with Mojave, and replaced the original, incompatible files in my main library by the converted versions. ist of the videos from the early iPhoto days had to be converted.
I also removed all PDFs and converted many photos that had been shared by friends and family from Windows PC and were still in the PICT and BMP format.
