consolidate all Photo Libraries into one and make one system Photo Library
How can I consolidate or merge all Photo Libraries into one and make it the system Photo Library?
How can I consolidate or merge all Photo Libraries into one and make it the system Photo Library?
You can not totally - this article describes the various options and the draw backs of each - Notes on Migrating an iPhoto Library from iPhoto to Photos for Mac
the bet solution and the closest to a true merge if using High Sierra with IOS 11.x and successively upload libraries to iCloud Photo Library - at the end you have a complete merge except for projects so if you have one ibrary with projects yu want do it last so it keeps the projectws and gets all of the other library photos merged into it and you set it as the system library in the Photos preference ==> general
Next best (and a lot less complete) is PowerPhotos which loses the ability to revert ot the original and keeps one version (the original or the edited version) as the original - all photos are merged but you lose a lot of the power of Photos and the no destructive editing for existing photos -- PowerPhotos has the ability to view multiple libraries adn some people use it to view photos and never merge the libraries - even if you use the recommended ICPL to merge PowerPhotos is a worth while and very useful utility to have
Least effective is exporting from one library and importing into another one
and the Mac world article is pretty much worthless since it is about Photos 1.0 and we are now at 3.0 and it does not even mention the ICPL method which is by far the best
LN
consolidate all Photo Libraries into one and make one system Photo Library