Thousands of duplicates as Photos forgets what it already imported.

Photos has Alzheimer's.

This issue persists maybe six months at this point.

I downloaded Gemini to detect and delete thousands of duplicate imported images but of course whenever I connect the iPhone to the iMac via the lightning to USB cable, Photos for the desktop is prompted to open and ask if I want to import the same images all over again. Most of these image captured years ago.

Prior to the past six months or so - as far back as 2011/2012 or so - the import, synchronisation, distribution, backup and downloading of original images to the iMac appeared seamless.

Something has changed recently.

For me the immediate solution may be to disable the import prompt presumably via Photos preferences.

Images captured in the present - for instance, today - seem to be imported automatically via WiFi or via mobile data if I allow it.

Since 2011 when I bought my first iMac (and should have been buying bitcoin) I was locally storing original images via iPhoto, iMovie and Aperture.

I always want the originals or "masters" stored locally on my own hard disks for obvious reasons.

However, Apple's iCloud did offer some redundancy and convenient synchronisation features across their range of devices.

I eventually opted for a 2TB iCloud subscription to keep a backup of mostly images captured on the iPhone and downloading the full sized images to the iMac via Apple's cloud.

Devices like successive iPhones and iPads were all set to optimise storage space.

Someone else describes the issue. I was unable to respond because discussions are closed after a period of inactivity:

I have an ipad, iphone & imac all used to sync with iCloud photo library and this has been working fine for past 2 years, I have not changed any options, as far as I am aware. I do not import manually other than when connecting iphone to mac via cable and it fires up photos asking what I want to import. I do this circa every few months but only to check for OS upgrades really, everything else is done over WIFI for both iphone & ipad.