Apple Books app issues during iCloud Backup process

Hi Justin,

Thank you for clarifying — this inverse behavior is actually quite revealing and points to a specific iCloud/Books behavior that's different from the standard scenario I described.

Here's what's likely happening:

**Why turning OFF Books increases the backup size:**

When Apple Books is toggled ON in iCloud Backup settings, it typically uses iCloud Drive sync (not the iCloud Backup) to store its PDF data. So while it appears in the Backup Details list, the actual data is being offloaded to iCloud Drive, keeping your backup size smaller.

When you toggle Books OFF in iCloud Backup, iOS may switch the PDF storage method — it can move that ~40GB of PDF data OUT of iCloud Drive sync and INTO the regular device backup, causing the backup size to jump.

**Regarding Files app vs Books app:**

Yes, this is directly related. PDFs that live in iCloud Drive (accessible via the Files app) and PDFs inside the Books app can overlap in iCloud's accounting. When you disable Books from Backup, the system may re-categorize those PDFs as device data to be included in the regular backup.

**What to try:**

1. Check Settings > [Your Name] > iCloud > iCloud Drive and see how much storage Books/PDFs are using there

2. Go to Settings > [Your Name] > iCloud > Manage Account Storage > Backups > [Your iPhone] and check what's listed under Books

3. Try toggling Books ON in backup and waiting for iCloud to sync before checking the Next Backup Size again

The '+Zero KB' for new PDFs may also confirm iCloud Drive is handling them (not the backup).

This is likely a known quirk of how iCloud handles Books/PDF data. You may want to submit feedback via Feedback Assistant for Apple to clarify the documentation.

Hi! This is a really interesting observation, and there are a couple of things going on here that explain both behaviors:

Regarding the backup size difference (44.5 GB vs 84.87 GB):

When Apple Books is included in the iCloud Backup, it backs up not just the app itself, but also all your downloaded books, audiobooks, PDFs, and reading data. The ~40 GB difference you're seeing is almost certainly your entire Books library (downloaded books, samples, etc.). The app was downloaded to your device but the content within it is what's making the backup so much larger. This is expected behavior — Apple Books can hold a large amount of content.

Regarding the duplicate "Turn Off and Delete from iCloud" button:

This is a known UI bug in certain versions of iOS. It sometimes occurs when iCloud Backup is scanning/indexing the app list while you have the Backup Details screen open. The duplicate button typically disappears on its own when you exit and re-enter the screen. If it persists, a restart of your iPhone usually clears it.

What you can do:

1. If 84 GB backups are too large, consider selectively removing downloaded books from the Books app (long press a book > Remove Download). This reduces the backup size significantly.

2. Alternatively, you can exclude Books from the backup if you're okay redownloading your books after a restore.

3. For the duplicate button bug, exit the screen and re-enter, or restart your iPhone.

Hope that clarifies things!

v1v3km wrote:

This is likely a known quirk of how iCloud handles Books/PDF data. You may want to submit feedback via Feedback Assistant for Apple to clarify the documentation.

Maybe let your AI program know that Feedback Assistant is only relevant for Developers testing beta versions of software or actually test your answers before posting. I know that requires more work, but that is what is expected on this Community Forum. Anyone can post a question into Google and copy/paste the AI response. That requires no actual knowledge at all and as has been seen often times produces wrong information because the data is trained from Social Media posts where they don't even have to be true.

If I relied an AI responses I would be adding glue to my pizza to keep the cheese from sliding off or eating rocks to increase my mineral intake. Yes, those are actual AI responses and there are entire websites devoted to alerting users so they don't foolishly believe what has been said.

Maybe read the Terms of Use for this site as we have all seen this type of behavior before.

• Material submitted must be your own work or work to which you have a license. By posting a Submission, you warrant and represent that you own or otherwise control all of the rights to the information contained in your Submission. Apple has the right, but not the obligation, to remove any Submission that is wholly or substantially created by using generative AI tools. Generative AI tools include image generators (such as Midjourney or Stable Diffusion), large language models (such as GPT-4, PaLM, or Claude), code generation tools (such as Copilot), audio generation tools (such as VALL-E or resemble.ai.), or any other tool or system that primarily functions to automatically generate content or answers for a user.

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v1v3km wrote:

Hope that clarifies things!

Hello~ Clarifies things? Using AI to post here usually only confuses things even more…

~Katana-San~

Hello~ Well done and +1

~Katana-San~