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Am I able to delete the "migrated photo library" after I convert from iPhoto to Photos?

I've recently converted to the new Photos app in OSX and have noticed there is a large library with the iPhotos library logo (52.1Gb). I'm wondering if I can safely delete this without losing any pictures from my Photos library. or if not, what is its purpose and why is it so large?


Here are some screenshots of an OmniDiskSweeper sweep of my home drive and of finder:


User uploaded file

User uploaded file

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Any help is greatly appreciated as I have very limited disk space!

MacBook Pro with Retina display, OS X Yosemite (10.10.3)

Posted on May 1, 2015 10:44 AM

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Posted on May 1, 2015 11:05 AM

The Photos Library and the Migrated iPhoto Library are sharing the image files by hard links.


You would not gain any additional disk space by deleting the "iPhotos library.migratedphotolibrary", but would lose the opportunity to use your library again with iPhoto or to repeat the migration, if you should discover that some photos did not migrate correctly. The reported size of the library is misleading. The filesystem counts them twice, because hardiness look like regular files.

See these documents:


Wait with deleting the iPhoto library until you are very sure, that each and every photo migrated correctly, and you are happy with the workflow in Photos.


Are you using iCloud Photo Library? Otherwise the Photos Library and the Migrated iPhoto Library should have approximately the same size.

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May 1, 2015 11:05 AM in response to brandontoner

The Photos Library and the Migrated iPhoto Library are sharing the image files by hard links.


You would not gain any additional disk space by deleting the "iPhotos library.migratedphotolibrary", but would lose the opportunity to use your library again with iPhoto or to repeat the migration, if you should discover that some photos did not migrate correctly. The reported size of the library is misleading. The filesystem counts them twice, because hardiness look like regular files.

See these documents:


Wait with deleting the iPhoto library until you are very sure, that each and every photo migrated correctly, and you are happy with the workflow in Photos.


Are you using iCloud Photo Library? Otherwise the Photos Library and the Migrated iPhoto Library should have approximately the same size.

May 1, 2015 11:14 AM in response to brandontoner


Are there any other reasons why there would be such a large difference in the file sizes?

Did you ever sync the old iPhoto Library with iTunes? The it may contain an iPod Photo Cache, that can be quite large. (iTunes: Understanding the iPod Photo Cache folder)


You could open the old library in iPhoto and the new one in Photos and compare side-by.side, if events are missing. If you already have updated to iPhoto 9.6.1, you can directly click iPhoto in the Applications folder, select "Open iPhoto" from the panel that will pop up, and browse the old library in iPhoto.

May 1, 2015 11:35 AM in response to léonie

I have! And it seems that iPod cache is quite large. I think I'll go ahead and delete that and see if it reduces in size if I resync my device (I have reduced the amount of pictures I sync)


I have also deleted some files and events since trasferring to Photos (in an attempt to clear disk space). Would those changes reflect in the iPhoto library or is that a snapshot of my iPhoto library at the time of trasfer? I'm satisfied with my Photos library, so I may go ahead and delete the iPhoto one since its larger (I also have a backup on a drive of the full library before deleting)


Here is the memory distribution in both libraries:


User uploaded fileUser uploaded file

May 1, 2015 11:44 AM in response to brandontoner

Would those changes reflect in the iPhoto library or is that a snapshot of my iPhoto library at the time of trasfer? I'm satisfied with my Photos library, so I may go ahead and delete the iPhoto one since its larger (I also have a backup on a drive of the full library before deleting)

Any changes you did in Photos will not reflect in your old iPhoto Library. The changes do not sync between libraries. To reclaim the disk space you need to delete the photos in the iPhoto library as well.


If you have a full backup of the original library, it will be safe to delete the iPod Photo cache.

May 30, 2015 1:47 PM in response to léonie

I don't think you're right, at least on my computer. I've got two 99.5 GB files listed on my computer - one called iPhoto Library.migratedphotolibrary and one called Photos Library.photoslibrary.


I've now got messages that my hard drive is almost full. I ran Grand Perspective, and it also shows two huge files of the same size - with the names above.


So I don't see how it's two programs sharing one set of photos.

May 30, 2015 2:03 PM in response to tdrr

I don't think you're right, at least on my computer. I've got two 99.5 GB files listed on my computer - one called iPhoto Library.migratedphotolibrary and one called Photos Library.photoslibrary.

Hard links can be confusing, because they cannot be distinguished from the original files in the Finder.

The links between the original files in the iPhoto Library and the Photos library are hard links. A hard link to a file and the original file are both referencing the same entry (inode) in the file table. This way each of them is a regular file, but they are sharing the blocks on the disk. Because both are regular files, the Finder will show the full file size for both of them, and both your photo libraries will show the full size.

When you delete the iPhoto Library migrated, you will reclaim the disk space used for Previews , Thumbnails, and Faces, but not the disk space used for the Master folder. They will only be released, when you deleted the photos from your Photos library as well, since the files are shared.


See this link: Six Colors: The (hard) link between Photos and iPhoto

And Apple's document: Photos saves disk space by sharing images with your iPhoto or Aperture libraries - Apple Support


For example:

The original files in Photos are hard links to the original files in Aperture or iPhoto, but look perfectly identical:

The same original master file in the migrated Photos Library as in the original iPhoto Library:

User uploaded file


You can tell that it is a hard link from the identical inode number in the Terminal using the "ls -i" command:

I marked the inode numbers in red: The files are in different Masters folders, but have the same entry in the file table:


Last login: Sat May 23 07:46:46 on ttys000

Hermione:~ dreschle$ ls -i ~/Pictures/Aperture\ Library2015.migratedaplibrary/Masters/2015/05/23/20150523-185458/IMG_0107.jpg

37677881 ~/Pictures/Aperture Library2015.migratedaplibrary/Masters/2015/05/23/20150523-185458/IMG_0107.jpg

Hermione:~ dreschle$ ls -i ~/Pictures/Photos\ Library2015.photoslibrary/Masters/2015/05/23/20150523-185458/IMG_0107.jpg

37677881 ~/Pictures/Photos Library2015.photoslibrary/Masters/2015/05/23/20150523-185458/IMG_0107.jpg

Hermione:~ dreschle$

May 30, 2015 2:33 PM in response to tdrr

Use an external drive, that is connected by a fast connection, Thunderbolt or USB3 would be very good, and make sure the drive is formatted MacOS Extended (Journaled). Another filesystem will not work.


Prepare the drive as described here: iPhoto: Sharing libraries among multiple users - Apple Support

and Format external drives to Mac OS Extended before using with Aperture


This kind of documents has not yet been published for Photos, but the Aperture and iPhoto versions will also work for Photos.

Aug 7, 2015 5:54 AM in response to léonie

I'm also not sure about this. OmniSweeper still shows duplicated data, and the second library is being counted as reducing the overall footprint. My photos are now taking up 400 GB instead of 200 GB. 'hard links' or not, it appears to take up double the disk space. If it looks like a duck and quacks like a duck... it's probably a duck.


In other words, if the system thinks the space is taken up, what good does it do us that it's a 'hard link'?

Aug 7, 2015 9:57 AM in response to mediated

. If it looks like a duck and quacks like a duck... it's probably a duck.


In other words, if the system thinks the space is taken up, what good does it do us that it's a 'hard link'?

Hard linked files are exact duplicates of the originals. They are exact copies with the same file size. Once you create a hard link, it is for all purposes the same file as the original and most programs will count the used storage twice. But the hard linked files are using exactly the same disk blocks as the original file - both files are sharing one entry in the file table. The storage is used only once, even if both libraries have several hundred GBs.

If you no longer need the original iPhoto Library go ahead and delete it after creating a backup copy on an external drive. And compare the free disk storage before and after the deletion of the iPhoto Library. You will gain considerably less free storage than the size of the iPhoto library.

Mar 19, 2016 11:33 AM in response to brandontoner

In reading through all this, I just want to ask if I am making the correct decision in my situation - I am moving my wife's data from an old iMac to a new one, it is going SLOOOOOW due to the size of her iPhoto libraries, one is over 200GB!


Am I correct in thinking, that I only need to move over the NEW Photos library, and I can abandon the old migrated one. (I'll still back it up to a hard drive before wiping the old iMac to donate)


It will save a lot of time, if not space, if I only have to move the one new Photos library.


Thanks!

Am I able to delete the "migrated photo library" after I convert from iPhoto to Photos?

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