Also, can I delete the old iPhotos libraries? That is, are all photos transferred to the new Photos libraries? I want to avoid duplications.
I strongly recommend to keep the old iPhoto libraries and not to burn your bridges immediately after the migration, for several reasons:
- It will only look, like the iPhoto Library and the new Photos library were using twice the storage, but they are sharing the storage for the images and are using less storage than the combined size on the disk, see this support document:
Photos saves disk space by sharing images with your iPhoto or Aperture libraries - Apple Support
and also: Six Colors: The (hard) link between Photos and iPhoto
- If you delete the old iPhoto Library, you will not gain much storage back. It is save to delete the iPhoto Library, but I would wait untill you are sure that the migration went well and no photos are missing. Looking at the thumbnails in the browser does not ensure, that the original image files are there. Only editing or exporting a photos will ensure it migrated well.
- Also, you may need to finish your projects in iPhoto, the projects do not migrate well. See: How Photos handles content and metadata from iPhoto and Aperture - Apple Support
- Sometimes you will need to repeat the migration, if you should encounter problems, that can only be repaired in the original iPhoto Library running iPhoto. Photos repair tools are not yet as powerful as iPhotos.
And if you discover, that you do not like Photos and want to revert to iPhoto, you will need your old library.
At least, keep a backup copy of the iPhoto Library and the iPhoto application.
In addition to the two recommendations above:
Before you migrate your iPhoto Library, finish any book or calendar project in iPhoto. After the conversion it will be more difficult.
If the iPhoto Library is on an external drive, check the file system of the drive. You cannot migrate a library that is on drive, where the file system is not MacOS Extended (Journaled). And the library must not be on a Time Machine drive. If either of the above applies, move the library to a different drive, that is correctly formatted.
To convert the library, you can simply drag it onto the Pkotos icon in the Dock.