Today when I loaded photos from a folder in finder, some of the photos did not open. The message I received said “The source file could not be found.”. What does that mean? Why would some load but not others? Thanks!
If the folder was one that is in iCloud Drive, or any of the other similar cloud services, it could mean that the files have not yet synced onto your computer from the cloud server. This might happen, for example, if you have ‘Optimise Mac Storage’ enabled in Settings->iCloud. There would be a ‘placeholder’ in the folder instead of the real file.