Here are the extensive notes I made when she handed me her old computer, a MB Pro, 2015, running Catalina:
N.B. My aim here is to be sure that ALL her photos will end up in Photos.app on her new MB Pro.
Also, can anyone understand why two Photo Libraries would each contain 11,121 Photos, 84 Videos, 10 Items while one of them is 51.45 GB and the other is 40.26 GB?
THE DEFAULT/SYSTEM LIBRARY - When I open Photos on that machine the Library it opens contains:
Photos Library 51.41 GB Created 4/15/16; Modified 3/9/20
Contents: 11,121 Photos, 84 Videos, 10 Items
ON THE DESKTOP of her computer reside two more Photo libraries
• 1. iPhoto Library 52.89 GB Created 12/25/2012; Modified 7/7/2018. When you double click on this Library’s icon, you get [Cannot open migrated library. The content of the iPhoto Library has already been migrated to Photos. Open Photos to view your library or use a compatible version of iPhoto to open this iPhoto library].
• 2. iPhoto Library 40.26 GB Created 8/21/21; Modified 8/23/21. When you double click on this Library’s icon, the photos open in Photos.app and Contents are 11,121 Photos, 84 Videos, 10 Items
QUESTION: I interpret this to mean that the number of photos in Photos Library 51.41 GB and in iPhoto Library 40.26 GB are the same [11,121 Photos, 84 Videos, 10 Items], yet the size in GB differs. One is 51.41 GB and the other is 40.26 GB. But why the difference in GB size??
**************************
The EXTERNAL HDD she gave me Contains:
iPhoto Library 1 - 41.84 GB Created 8/21/21; Modified 7/3/2023
iPhoto Library 2 - 40.45 GB Created 8/16/2019; Modified 7/3/2023
iPhoto.Library.migratedphotolibrary 12/25/2007; Modified 6/29/23
*************************
When you launch Photos app with Option key, 4 libraries are offered:
Photos Library (System Photo Library), i.e. Default library / last modified 3/9/20
iPhoto Library 1 / last modified Yesterday 9:41
iPhoto Library 3 / last modified Yesterday 4:26
iPhoto Library 2 / last modified Yesterday 9:17
Choosing iPhoto Library 1: says Updating Library…then [The library could not be opened (4302).
Choosing iPhoto Library 3 opens that Library. Contents are 10,023 Photos, 102 Videos, 9 items and no blank thumbnails
Choosing iPhoto Library 2 says Updating Library…then [The library could not be opened (4302)
So, on the external HDD are two libraries that cannot be opened
********************
Did a Safe Boot and tried to open the recalcitrant libraries again. No change; cannot open them. (4302) error once again.