MacOS Catalina does not sync photos with iOS Devices

I too have had this problem. It seemed that pre-Catalina Apple had finally gotten USB/Photos synching fixed, but then they broke it again in Catalina. I spent hours on half a dozen days going over things with them pre-Catalina, but with a new baby haven't had time to get into it with them on Catalina except to file bug reports. Thank you all for following up.

Last week I synced my phone, after removing all photos in the manner I've been forced to sync since the Catalina upgrade. This sync was successful in that it imported all photos and movies with no duplication. Today I attempted to sync new photos twice without removing the photos. The first time it actually removed about 30 photos and also some videos. The second time it removed about three thousand photos and some videos. It failed to sync by not adding the new photos. My workaround is to remove all photos and then sync again.

That procedure works for me, it worked already before the last updates. But it‘s unacceptable to be forced to perform this entire process in order to get a good synchronization; it takes too much time and it’s annoying. And mostly, it was fine before the last major update in the past September. At the moment, Apple really sucks. This is absolutely unacceptable.

I found a way to workaround the photo sync.

My hardware: MacBook pro Retina 2015, iPhone 6s, iPad pro 9.7" first generation plus my wife's iPhone 11 and iPad Air 2 2014. All of them with the recent OS updates.

Here my way to sync the Photos from my MacBook pro to the iPhones and iPads:

1st unselect Photos in the iCloud settings of all devices

2nd connect the iPhone/iPad via lightning cable with the Mac

3rd make a backup of the iPhone/iPad

4th in the Finder select all contents but photos to be synced

5th select the photos to be synced from the folder of the Mac (in my case the path is users/shared/data/photos1, photos2, photos 3. Each of these photos folders has several subfolders from 50 to 500.)

Important: Stay on the Photos page of the sync tool!

6th click on "apply".

7th if there is an error message like "folder 'unknown' not found" select the folder on the Mac again and click on "apply" or "sync", whatever is offered.

8th if it is still not syncing or even deleting your photos from the iPhone/iPad repeat step 7th.

This worked for all my devices. The only problem: I have to run one more sync for the music.

Next I will try it with my new iPad pro 11" 2020. I'm waiting for the USB-C adapter to connect it with my Mac.

Next experiments I will do: Syncing with Win 10 based iTunes.

I tried it using BootCamp, but unfortunately this doesn't give acces to the Mac partition.

Next I will try Win10 with Parallels on my Mac.

Perhaps also with VMWare and Virtual Box.

Finally I want to say, that Apple was an excellent example for reliable Hardware and software as well. This was their big advantage over the competitors and this was the reason for the relatively high prices they could charge from the customers.

The original thread that this restarted didn't involved iCloud Photos, so given this is a restart of it, most people in the original thread weren't using iCloud photos merely USB-C so step 1 isn't applicable. Just FYI.

@Gulliver, maybe clarify in the first post as to whether this is exactly like the original thread where they say "I do not use iCloud photos."

I am also experiencing the same thing. The status bar is a massive improvement and the process appears to have speeded up from over 24 hours to about an hour BUT ...... when the process appears to have finished, (I.e status bar disappeared and the eject icon is shown for the iPad), the photos in Photos App on the iPad are showing many empty albums and all the Albums still say they were ‘syncing’, I have kept it running for 2 hours and it seems to be still copying photos onto the iPad. You can actually see them being added! I’m going to keep it running for 24 hours to see what happens. Will keep you posted!!

Update: the iPad has remained connected to the MacBook Pro since the syncing process completed at about 11am yesterday (approx 28 hours ago). 

all photo albums appear to have now got photos in them BUT some of the albums when I click into them still have the word ‘syncing’ at the end. When I look into them they appear to have all the photos but there are quite a few movies missing. The storage space on the iPad is not changing so have now taken the decision to disconnect the iPad from the MacBook Pro. 

My conclusion is - after the syncing process appears to have completed IT HASN’T. Leave it connected until you are happy you have most of your photos. The syncing message in some albums may still remain! 

When I have the motivation I am going to try the process again but not to include videos this time. Hopefully Apple will try some of these tests as well. 

Unfortunately I spent a few hours on the phone to Apple many months ago about the syncing process . I didn’t get anywhere and I don’t believe they understand the issues and how poor the software is. They just suggested I use iCloud which I don’t want to do. They don’t seem to admit there are problems with this software.

10.15.5 final still hasn't helped sync process. They did contact me back in March and I've been sending logs after each beta (and now final) version. So far it hasn't helped.

I had thought they were making progress, but the 10.15.5 sync had 1000s of missing photos just from one album.

I am going to remove all photos and try to resync them.

I worked through the above mentioned thread - unfortunately, none of the hints worked for me.

My experience is that it has improved for the first sync After being cleared, but still has missing pictures, then in subsequent syncs gets duplicates and a big mess.

Yes, it is definitely not solved. Thanks for opening a new thread.

Same here, facing the same problem even after updating my devices.

Had a 70 minutes support session with apple today. I showed how the sync does not work with two remote connections to my Mac and my iPhone. Tomorrow I will have the session with the senior supporter