Book Isle app lock: protect the shelf and check unlocking

English translation of the Chinese original, translated on 2026-10-23. The article body uses automated translation; app descriptions, historical reading notes and video subtitles receive separate editorial checks. Original publication dates, attribution, code and version notes are retained.

A private bookshelf may contain unpublished work documents, personal notes, and reading records. Book Isle's App Lock authenticates through system Face ID, Touch ID, or the device passcode. This guide shows how to enable it, check protection on reentry, and distinguish it from file backups and server permissions.

Confirm that device authentication works before starting

First confirm in system settings that a device passcode is configured and enable Face ID or Touch ID where supported. Book Isle invokes system authentication; you do not need to create an unfamiliar separate app password. If system authentication is unavailable, configure it first before enabling App Lock, rather than mistaking a device configuration issue for a bookshelf-file problem.

Before practicing, confirm that you can unlock the device normally and that important information has a separate means of preservation. Do not delete the app to test whether the lock can be bypassed, as deletion may remove local content. App Lock adds authentication to interface access; it does not replace system device protection or every data-backup strategy.

Enable App Lock in settings

Open Book Isle's “Settings,” enter the relevant “Privacy and Security” area, and find “App Lock.” Enabling it triggers system authentication; follow the on-screen instructions. After success, return to settings and confirm it is shown as enabled. If authentication was canceled or failed, tapping the switch alone does not prove protection took effect.

If prompted to enable Face ID, Touch ID, or a device passcode first, handle that in system settings and try again. Authentication methods vary by device; a Touch ID device does not need a Face ID-only button. After enabling the lock, keep this practice book on the shelf. Later checks need not involve genuinely sensitive documents.

Check behavior when leaving and reentering

Return to the system home screen, reopen Book Isle, and look for authentication or a “Private Library Locked” message. After authentication, you should return to the bookshelf or previous interface. On the first test, cancel authentication to check that book content is not exposed directly, then retry through “Unlock.”

You can also check whether a protection screen covers the preview in the app switcher, then return to authenticate. This verifies what happens during your everyday app switching without recording private content. Do not infer identical protection in every situation from a brief change during a system animation. Use the visible behavior of your current device and version as the check.

Understand retrying and disabling the lock

After failed authentication, tap “Unlock” to invoke system authentication again. Depending on device status, the system may require a passcode or temporarily limit biometrics; follow its prompts. NAS login passwords, Apple Account passwords, and device unlock passcodes belong to different systems. Book Isle's App Lock does not ask you to enter a server password here.

To disable App Lock, first unlock the app, enter settings, then switch it off and complete any required authentication. Confirm that its status is disabled and reenter once to verify. This is a reversible setting change worth checking before using the device in another context you manage, but do not let a stranger enter your device passcode for you.

Manage exported files according to their destination

App Lock protects access to the Book Isle interface. It does not automatically put the same lock on notes, cards, or ebooks already exported to Files or Photos. A quote card saved to Photos uses Photos' own access method when opened there. Content shared to another app must likewise be managed under that app's rules.

For private notes, check whether the export destination is appropriate before saving. For long-term work records, choose a location you explicitly manage and clear filenames distinguishing private and shareable versions. App Lock does not mean every export is encrypted or will never sync to another device.

Protect the server and device separately

Book Isle's App Lock does not disable NAS guest access or change WebDAV, SMB, or Calibre account settings. The server still needs its own access control, and the device should still use a system passcode. Both help protect a private library but cannot replace one another. After remote connection details change, check the relevant connection settings.

If you use Book Isle on two devices, check each device's lock status and system authentication separately. Synchronizing reading records does not automatically configure device protection. On a new phone, first verify the local bookshelf, sync, and file availability, then enable App Lock and follow these checks so each completed step remains clear.

Frequently asked questions

Can I use App Lock without Face ID? The current implementation uses system device-owner authentication, which may include a device passcode or Touch ID. Available methods depend on device capabilities and system configuration. If the page says the lock cannot be enabled, follow its instructions to establish working system authentication first.

Can Book Isle recover a forgotten device passcode? App Lock relies on system authentication. Book Isle has no way to recover the system password for you. Use the device's official recovery process and consider its effects on local data. Uninstalling and reinstalling is not a lossless recovery method.

Does enabling App Lock mean every ebook is encrypted? No. App access authentication, file storage protection, server transfer, and exported-file protection are different layers. App Lock requires authentication to enter Book Isle. Files exported elsewhere are managed by their destination; use an appropriate file-protection tool if separate encryption is needed.

Sources and version

Information checked on October 23, 2026. The public release is Book Isle 1.1.3, requiring iOS / iPadOS 15.6 or later. This guide is based on public feature descriptions and their entry points. Interface labels may change with the version. See Official App Store description and Apple release information.