Sync stuck on “preparing to sync”

I've been on to Apple support this last couple of days with this very issue since updating to Sonoma 14.2 and iOS 17.2, although I have also seen it in the past. Apple's suggestion of safe mode reboot and then an OSX reinstall did not work.

So temp fix 1: Plug your phone in with the cable (as I will explain below) <CMD> + space and open up the activity monitor (or just open the app from LaunchPad). Search for MDCrashReportTool and force quit it. This is clearly part of the issue (although no idea why).

You should find that the sync will unstick and you will get access to your phone in Finder again. In finder, click on your phone and under "General", scroll down to "Options" make sure that the "Show this iPhone when on Wi-Fi" is deselected. With that off, I have found that I can sync normally now until the phone is unplugged (more below on that). Problem with sync over Wi-fi it is more difficult to get your phone to disconnect from the Mac (again see below solution) so until Apple fix this, best bet is cable sync only.

At this point, I find that syncing works fine, until I remove the cable/disconnect the phone. When I then plug the phone back in, I am back to square one with the stuck issue, however when I pull the cable out and plug back in, I find that it syncs fine. The MDCrashReportTool also doesn't get stuck after the unplug and reinsert.

Not a fix, I'm afraid, but at least for now, it got me able to sync my Mac and iPhone and not have to force shutdown my Mac every time. Hope this helps.

Syncing over Wifi also works fine for me if I kill "MDCrashReportTool" when the sync is stuck in "preparing to sync"; by the way, killing the tool can also be done in the Terminal via

killall -9 MDCrashReportTool

Still don't know why Apple seems unable to fix this. Again, my suspicion is that local syncing is now longer endorsed by the company... they'd rather have you subscribe to their streaming services.

I found a solution by Lightguitar which worked for me:

Same problem with iOS17.2.1 and macOS 14.2.1.

I discovered the following work-around. (But the whole thing is still quite annoying.)

1. When stuck in sync, pull-off the sync cable

2. Next, plug-in the cable again

3. Skip the generation of "Backup" to speed-up (it was generated just before the stuck)

4. The sync process goes on and finishes

Also I performed a few additional steps before sync attempts:

-switched off my apple watch

-deleted all music from the iPhone

After restoring all music back I noticed the same issue 'all greyed tracks in the music' in my watches. Solution was much easier rather than trying to sync MacBook with iPhone, I just deleted all music from the watches and added it again through watch application in the phone.

And I was disappointed to discover that new music app in watches doesn't allow anymore to switch music between different playlists on your phone. The only thing you can do in the phone with watches is to control music in current playlist.

Disabling the option "Show this iPhone when on Wi-Fi" is a good option in iOS 17.2.x to prevent batteries from draining silently due to infinite sync loops. However, it's not a sustainable fix.

The MDCrashReportTool will become stuck again, even with the cable. It is a random issue that only Apple can solve (if they feel like doing so).

I faced the same issue. And my wife has this issue too.

We use MacBook Pro 13 with Touchbar 2019 2 Tb3 ports and 4 Tb3 ports, macOS Sonoma 14.2/14.2.1 and two iPhone 13 mini iOS 17.2/17.2.1

Also I can add that during this stuck MacBook fans time to time start spinning at max speed and MacBook feels very hot. This behaviour is absolutely insane, feel my self loaded with devices which ones aren't able to work properly. Very annoying. And I noticed how iCloud uploading stucks during this sync stuck. Such types of issues make work unpleasant.

So strange that only a few users confirmed same issue here, because I'm absolutely sure almost everyone has it. Does it mean that regular user of iPhone/MacBook doesn't sync them? Lol, isn't it 'amazing'? So disappointed... uh, just noticed the date of this post, only a week passed... hm, let's wait for a few months more till get a fix from Apple

Well; I couldn’t succed… But for music purchased from iTunes store I found solution- albums/ songs are in fact hidden. So open Apple music, go to account settings, open Hidden Purchases and you will get a list. Now you can download. Unfortunately that doesn’t work for your music you ripped from yours original CDs …

Merry Christmas to all,

Mark.

I'm having the same issue here. I guess this is Apple's way to tell us "just Apple Music already". It sucks.