The Drawbacks of "Delete After Import"
This user Tip has been reformatted and moved to: The Drawbacks of Delete Items After Import When Importing to Photos
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When importing photos from an iPhone, a camera, or a card, the Import panel in Photos, iPhoto, Aperture, and Image Capture offers an option to delete the items after import. This is very convenient, because we do not have to find the items on the device and to delete them there manually.
Be very cautious, when using this option. It is risky to delete the photos directly at the first import to the computer, sight unseen and before we made the first backup.There have many photos been lost by "Delete after import" - it is a disaster waiting to happen. Just browse this forum. Sometimes Photos will crash, if it running out of storage or similar, and the photos will have been deleted from the card, but the photos Library may not yet have been updated on the disk. No way to recover the photos.Or, sometimes there is a problem with the cable causing transmission errors, and the imported photos may be unreadable. But with "Delete after import" you will not be able to repeat the import, if it went wrong and you suddenly see gray bars across your photos or other kinds of JPEG corruption.Seeing the thumbnails of your photos in the Import window is no proof, that the photos downloaded correctly to your Mac. The thumbnails are embedded in the original photos and you cannot tell from the thumbnails that the original image files will be readable. You cannot see the original image files during the import - you would be deleting the only copies of your photos from the device or the card.It is essential to wait with deleting the photos from the card, until you have seen the photos enlarged, after they have been imported to the Photos Library, and you are sure, that the originals can be read.Wait, until you have made the first backup of the new import, and only then delete the photos from the card or the device. This good practice is not too much extra work, and you will not risk to lose precious photos.A card can quickly be erased by reformatting it in the camera. And an easy way to delete photos from an iPhone, iPad, iPod is to connect the device to a USB port and then use Image Capture to delete the photos. Image Capture can delete from a device without importing.
The "Delete After Import" option will not be available on an iOS device, if iCloud Photo Library has been enabled on the device. This makes sense, because the Mac would have to delete the photos from iCloud. With iCloud Photo Library active, the originals of the photos are stored in iCloud and only mirrored in the camera roll.