Why does it take so long to update iCloud music library?

iCloud is Apple’s cloud storage service that allows users to store data such as photos, documents, and music online. The iCloud music library is a feature of iCloud that lets you access your music library from any device connected to your iCloud account. It works by storing your music library in iCloud and making it available on your iPhone, iPad, Mac, and other devices.

One common issue with the iCloud music library is that it can take a very long time to update and sync changes across devices. This long sync time can be frustrating for users who are trying to access their latest music additions and playlists from different devices. The length of the update depends on factors like the size of your music library, internet connection speeds, and any problems during the sync process. With large music libraries especially, the iCloud music library update can take hours or even multiple days in some cases. This delay prevents quick and seamless access to your music, which defeats the purpose of having a cloud-based library.

Size of Music Libraries

The size of music libraries has grown exponentially with the rise of digital music and devices that can store thousands of songs. In the past, music collections were limited to the number of physical albums, tapes or CDs that people owned. But with digital formats like MP3s and streaming services allowing endless music access, libraries have ballooned in size.

According to a 2011 study by Hypebot, the average digital music library contains 7,160 songs (source). However, enthusiasts on forums like Reddit have reported libraries many times that size, with over 30,000 songs or 1 terabyte of data being common among power users.

As personal libraries grow into the tens or hundreds of thousands of songs, updating and syncing them to iCloud understandably takes longer. Apple has to analyze each track’s metadata, upload those not already matched, and handle duplicates across devices – tasks that scale exponentially with library size.

Metadata Processing

iCloud scans and processes the metadata for each song uploaded to ensure proper matching, deduplication, and organization in the cloud library. This metadata can include information like the song title, artist, album, genre, release date, track number, duration, and more. With larger music libraries, there is substantially more metadata associated with each track that needs to be indexed and processed by iCloud.

According to the iCloud Design Guide, iCloud uses metadata query objects to obtain and update information on content stored in iCloud Drive in real-time. This allows Apple to continuously monitor changes to metadata as users edit or add new content.

The iCloud Metadata Attributes documentation further explains the different metadata fields maintained for each file such as timestamps, file attributes, and iCloud-specific fields like document change tag and document file UUID.

With music libraries potentially containing thousands of songs, processing all of this metadata on upload can be very computationally intensive for iCloud servers, which contributes to the longer upload times.

Uploading Songs

After identifying the songs you want to add to your iCloud Music Library, the next step is uploading the songs to Apple’s servers in the cloud. This involves transferring the song files from your local device storage to Apple’s iCloud servers.

The time it takes to upload songs will depend on a few factors. The most significant factor is your available bandwidth and internet speeds. Uploading lots of large, high-quality audio files is data intensive. On slower connections, the upload process will take considerably longer as data rates are limited.

According to Apple’s support article Use Sync Library with your Apple Music subscription, songs upload at a rate of around 200 KB per second on average broadband speeds. So a 5 minute song that is 5 MB would take around 25 seconds to upload. For a large music library, these individual upload times add up.

Optimizing your internet connection by using Ethernet instead of WiFi, upgrading your broadband plan, or moving closer to your router can potentially speed up upload times. But bandwidth caps and real-world speeds may still bottleneck the process.

Matching Songs

One of the main reasons updating an iCloud music library takes time is because of the song matching process. iCloud uses an acoustic fingerprinting algorithm to match songs in your library to songs already available in Apple Music (Source: https://discussions.apple.com/thread/7867300). This allows Apple to provide you access to high-quality matched versions without needing to re-upload songs.

The larger your music library, the more songs iCloud needs to match, which increases the time required. Apple has worked on improving the accuracy of the matching algorithm over time to limit issues caused by inaccurate matches (Source: https://www.billboard.com/pro/apple-improves-song-matching-algorithm-for-apple-music-users/). But matching tens of thousands of songs still takes significant processing time. The matching process alone can take hours or days for very large libraries.

Each song goes through acoustic analysis to identify the audio fingerprint, which is then compared to the Apple Music catalog. The algorithm has to match minute details in the audio to find the closest match. With a library of just a few thousand songs, this can take a while as each match requires substantial processing power. The more songs that need matching, the more exponentially difficult the process becomes.


One key step that takes significant time during the iCloud music library update process is deduplication. iCloud scans the entire music library, identifies duplicate songs, and removes the duplicates. This is done to save storage space and avoid syncing duplicate songs across devices. The larger the music library, the more potential there is for duplicate songs, which means more processing time required for deduplication.

For example, a user may have the same song downloaded from multiple sources over the years, like from iTunes purchases, ripped CDs, and Apple Music downloads. Or they may have duplicates created inadvertently through syncing errors. Removing these duplicates requires iCloud to analyze every song’s metadata like the track name, artist, album, play length and more to definitively match duplicates. This analysis and removal of duplicates takes substantial computing time especially for large libraries.

Overall, deduplication is a key reason why updating an iCloud music library can be slow for users with large collections. The system has to meticulously scan a substantial number of songs and identify duplicates based on metadata matching. This comprehensive deduplication process ensures storage efficiency but results in a prolonged update time.

Downloading Songs

One of the key steps when updating your iCloud Music Library is downloading the full versions of your matched songs to each device [1]. When you match a song that’s already in your library to an iTunes version, it doesn’t automatically download the full song file – it essentially just points to the song in the cloud. So you still need to download the full, high-quality version to each device.

This downloading process takes time, bandwidth, and storage space on each device. For large libraries, it can take hours or even days to download all the matched songs. The time depends on your internet connection speed, the size of your library, and how many devices you need to sync. Each song is typically around 5MB, so thousands of songs means gigabytes of data to download. This is why updating your iCloud Music Library seems to “take forever.” [2] The process runs in the background and you may not realize it’s still occurring.


Once the upload process is complete, iCloud will verify the completeness of the music library before syncing it across devices (Apple Support, 2022). This verification step is crucial to ensure all songs and metadata are accurately copied. The larger the music library, the more time iCloud will need to fully verify every track.

During verification, iCloud scans the uploaded library and matches the songs against the Apple Music catalog. It checks that metadata like song titles, artist names, album information, play counts, playlists, and more are intact. iCloud also verifies that duplicate tracks are removed and consolidated (Ritchie, 2022). This deduplication process compares audio waveforms to determine that only one copy of each unique song is kept.

The verification stage tends to be lengthiest for users with enormous music libraries, sometimes containing over 100,000 songs. The more tracks iCloud must scan, match, and deduplicate, the longer the verification will take before completing the sync to all devices.


If the update to your iCloud Music Library is taking a long time, try troubleshooting some common issues that can delay the process. Larger libraries in particular often run into problems during matching and deduplication that prolong the update time.

One of the most common issues is mismatching or duplication between the songs on your devices and in iCloud. If you have the same songs saved in multiple places with slight differences like metadata or file formats, iCloud struggles to match them correctly. This results in duplicate copies in your library that then need to be manually deduplicated, which adds time to the update.

To help avoid mismatching, you can consolidate your music collection into one organized folder before starting the iCloud update. Removing any duplicate files yourself beforehand allows iCloud’s matching algorithms to work more efficiently.

You can also check Apple’s system status page[1] during the update to see if there are any known issues delaying iCloud services. If Apple reports problems on their end, it’s best to wait and try again later once those issues are resolved.

Overall, larger libraries require more processing time to match and upload songs, deduplicate files, and download the updated collection back to your devices. So the larger your collection, the longer the update will take even without any issues. Being patient and troubleshooting common problems can help get your iCloud Music Library updated eventually.


Updating your iCloud Music Library can be a lengthy process for several reasons. As discussed, the size of your library is a major factor. Larger music collections with tens of thousands of songs naturally take longer to scan, match, upload, and process. Metadata and duplication checks also add time, as Apple’s servers work to catalog and optimize each track.

The entire process involves scanning a local library, uploading any new or unmatched tracks, downloading matched songs, eliminating duplicates, and verifying everything syncs correctly across devices. Each step in this sequence requires time and processing power. For very large libraries, it may take hours or days to fully update iCloud Music Library. Patience is key throughout this intensive but necessary process.

In summary, the size of your library along with metadata processing, file uploading/downloading, deduplication, and verification combine to explain why iCloud Music Library updates can be slow. But the end result is having your entire music collection securely stored and available across all your Apple devices.