Now that I have cleaned up my duplicate photos problem in my Photos Library, is there any problems with removing my iPhotos Library? It looks like all my photos were migrated into Photos, but the iPhotos Library is still there and takes up considerable file space. Can I just delete it or will it cause me problems?
iMac 27″ 5K, macOS 11.1
If you are happy that all of your photos have been migrated to the new Photos library then you can delete the old iPhoto library without any problem.
However, you may not save as much space as you think. Whilst Finder will show both libraries as being, say 50GB each; if you are running the new version of Mac OS under APFS when the new Photos library was created instead of copying each photo into the new library, your Mac simply creates a hard link to the relevant file in the old library. Therefore, whilst it would appear that you have two libraries of 50GB each, in reality you are only using 50GB or so of space. When you delete the old iPhoto library your Mac will just move the relevant files into the new Photos library.
If you are happy that all of your photos have been migrated to the new Photos library then you can delete the old iPhoto library without any problem.
However, you may not save as much space as you think. Whilst Finder will show both libraries as being, say 50GB each; if you are running the new version of Mac OS under APFS when the new Photos library was created instead of copying each photo into the new library, your Mac simply creates a hard link to the relevant file in the old library. Therefore, whilst it would appear that you have two libraries of 50GB each, in reality you are only using 50GB or so of space. When you delete the old iPhoto library your Mac will just move the relevant files into the new Photos library.
This is a good article by Leonie that explains the processes for migration.
iPhoto Library
