To resolve the issue of your Book Crawler app reverting to a trial version, follow these detailed steps:

1. Check your purchase status: Ensure that you have successfully purchased the app and that your payment was processed correctly. Sometimes, payment issues can lead to the app reverting to trial mode.

2. Sign out of your Apple ID: Go to your iPhone’s settings, tap on your Apple ID at the top, scroll down, and select 'Sign Out.' This will log you out of your Apple account temporarily.

3. Restart your device: Press and hold the Power button until you see the "slide to power off" option, then swipe to turn off your iPhone. Once it's completely off, press the Power button again to restart it.

4. Sign back in to your Apple ID: After your iPhone has restarted, go back to the settings and sign back in with your Apple ID. Enter your credentials carefully to ensure that you are logged in properly.

5. Reopen Book Crawler: Launch the Book Crawler app again. Check if you are still experiencing the trial version issue.

6. Restore your purchase: If the app shows trial mode again, look for a "Restore Purchase" option within the app's settings. This feature typically allows users to regain access to paid features. Tap on it and enter your iTunes password if prompted.

7. Reinstall the app: If the above steps do not work, consider deleting the app and reinstalling it. Hold down its icon until you see the option to delete it, then confirm. After that, visit the App Store and download Book Crawler again.

8. Contact support: If you have tried everything and the issue persists, reach out to Book Crawler support for assistance. You can find relevant help on their support page, which may include additional troubleshooting steps - learn more.

Following these steps should help you restore full functionality to your Book Crawler app and allow you to add books again.

Why does the Book Crawler app lose its paid status?

The Book Crawler app may lose its paid status for several reasons. Here are the primary factors contributing to this issue:

1. App Glitches and Bugs: Users have reported that the app can become glitchy after updates. Malfunctions such as features not working correctly can cause the app to revert to trial mode. For instance, problems with the ISBN scanner and other functionalities have been noted by users - learn more.

2. Database Conflicts: If the app detects a previous version of your database that contains more books than your current version, it may revert to trial mode. This is typically a safeguard to prevent data loss and ensure that the app functions correctly. Make sure to check the integrity and size of your database - learn more.

3. Account Verification Issues: Sometimes, issues with the Apple ID associated with your purchase can lead to the app losing its paid status. Ensure that your Apple ID is logged in properly and that there are no purchase issues with your account.

4. Reinstalling the App: If you delete and reinstall the app, it may not recognize your previous purchase unless you have restored it properly. Always use the "Restore Purchases" feature within the app settings after reinstalling to regain access to paid features - learn more.

5. No Longer Supported: There are indications that the Book Crawler app may have become outdated or unsupported. Users have expressed concerns about its functionality over the years, suggesting that it could be less reliable due to lack of updates - learn more.

To prevent your app from losing its paid status, regularly back up your data and keep your application updated. If problems persist, contacting customer support may offer a direct solution.