Some Apple Music Subscribers Experiencing Library Syncing Issue Across the iPhone and Mac

Over the past few months, some users have been unable to sync their Apple Music library between their iPhone and Mac, seemingly due to a bug.

iOS 17 Apple Music Feature
Affected users receive the following error message in the Music app on the Mac:

Genius results can't be updated right now. An unknown error occurred (18004).

There are complaints about the issue across the Apple Support Community, MacRumors Forums, Reddit, and elsewhere on the internet.

The underlying cause of the issue is unclear, and it's not entirely clear if a fix will require software updates, or if Apple can implement a server-side fix. We've reached out to Apple for comment, and we'll update this story if we receive a response.

This issue comes after another Apple Music bug related to playlists was fixed last month.

Popular Stories

apple watch ultra yellow

What's Next for the Apple Watch Ultra 3 and Apple Watch SE 3

Friday April 25, 2025 2:44 pm PDT by
This week marks the 10th anniversary of the Apple Watch, which launched on April 24, 2015. Yesterday, we recapped features rumored for the Apple Watch Series 11, but since 2015, the Apple Watch has also branched out into the Apple Watch Ultra and the Apple Watch SE, so we thought we'd take a look at what's next for those product lines, too. 2025 Apple Watch Ultra 3 Apple didn't update the...
iphone 16 display

iPhone 17's Scratch Resistant Anti-Reflective Display Coating Canceled

Monday April 28, 2025 12:48 pm PDT by
Apple may have canceled the super scratch resistant anti-reflective display coating that it planned to use for the iPhone 17 Pro models, according to a source with reliable information that spoke to MacRumors. Last spring, Weibo leaker Instant Digital suggested Apple was working on a new anti-reflective display layer that was more scratch resistant than the Ceramic Shield. We haven't heard...
iPhone 17 Air Pastel Feature

iPhone 17 Reaches Key Milestone Ahead of Mass Production

Monday April 28, 2025 8:44 am PDT by
Apple has completed Engineering Validation Testing (EVT) for at least one iPhone 17 model, according to a paywalled preview of an upcoming DigiTimes report. iPhone 17 Air mockup based on rumored design The EVT stage involves Apple testing iPhone 17 prototypes to ensure the hardware works as expected. There are still DVT (Design Validation Test) and PVT (Production Validation Test) stages to...
Beyond iPhone 13 Better Blue

20th Anniversary iPhone Likely to Be Made in China Due to 'Extraordinarily Complex' Design

Monday April 28, 2025 4:29 am PDT by
Apple will likely manufacture its 20th anniversary iPhone models in China, despite broader efforts to shift production to India, according to Bloomberg's Mark Gurman. In 2027, Apple is planning a "major shake-up" for the iPhone lineup to mark two decades since the original model launched. Gurman's previous reporting indicates the company will introduce a foldable iPhone alongside a "bold"...
iPhone 17 Air Pastel Feature

iPhone 17 Air Launching Later This Year With These 16 New Features

Thursday April 24, 2025 8:24 am PDT by
While the so-called "iPhone 17 Air" is not expected to launch until September, there are already plenty of rumors about the ultra-thin device. Overall, the iPhone 17 Air sounds like a mixed bag. While the device is expected to have an impressively thin and light design, rumors indicate it will have some compromises compared to iPhone 17 Pro models, including only a single rear camera, a...
iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching Later This Year With These 13 New Features

Wednesday April 23, 2025 8:31 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of April 2025: Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone ...

Top Rated Comments

arkitect Avatar
17 months ago

Unreliable sync was the reason I gave up on Apple Music during a 90-day trial a couple of years ago. You know what service never gave me that problem? Every competitor I've ever tried (Pandora, Spotify, Deezer).
Exactly this.

I was burned by Apple Music in the transition from iTunes to Apple Music — my carefully curated music library literally — yes, literally — destroyed.

An 800GB+ music library that had been carefully sorted in albums and playlists. Mangled.
partial albums uploaded. Lossless files replaced by lossy.
Cover artwork? Pffft. Mixed and matched… missing.
Artists mixed up and ignored.

Broke my heart.

Unless there is a major rebuild from the foundations up, I will never be tempted to again.

Why other services could achieve it and the giant Apple cannot is a mystery.

And yet, how often do we hear that Apple really cares about music. "It is in our DNA" they say… yeah sure.
Score: 19 Votes (Like | Disagree)
mrmister Avatar
17 months ago

I was burned by Apple Music in the transition from iTunes to Apple Music — my carefully curated music library literally — yes, literally — destroyed.

An 800GB+ music library that had been carefully sorted in albums and playlists. Mangled.
partial albums uploaded. Lossless files replaced by lossy.
Cover artwork? Pffft. Mixed and matched… missing.
Artists mixed up and ignored.

Broke my heart.
I have never subscribed to Apple Music because of stories like this one. And syncing to my iphone has steadily become more and more of an ordeal—so much so I often just drop new material onto the phone with WALTR PRO, an app that exists to basically do what Apple can't be bothered to figure out.

Disgraceful that the people who invented the iPod can't do music and playlist transfers. This shouldn't just work—it should be seamless.

It's awful.
Score: 18 Votes (Like | Disagree)
Motawa Avatar
17 months ago
Thanks for mentioning it! Maybe Apple will now give at least just a little ****.
Score: 14 Votes (Like | Disagree)
erikkfi Avatar
17 months ago
Unreliable sync was the reason I gave up on Apple Music during a 90-day trial a couple of years ago. You know what service never gave me that problem? Every competitor I've ever tried (Pandora, Spotify, Deezer).
Score: 12 Votes (Like | Disagree)
Bustycat Avatar
17 months ago
The more Apple Music syncs, the more albums get split.
Score: 11 Votes (Like | Disagree)
vegetassj4 Avatar
17 months ago
Remember the good ole days when you would plug in your iPhone to power, and it would wirelessly wake your Mac, sync, backup, etc. with iTunes then the Mac would resume sleep?

Pepperidge Farm Remembers™

Attachment Image
Score: 7 Votes (Like | Disagree)