Hi there! I’m sorry to hear that your app is crashing while syncing music. Let's work through this together!

First, could you tell me a bit more about the situation? For example, which app are you using to sync music, and does the crash occur at a specific point in the syncing process?

In the meantime, here are a few basic troubleshooting steps you can try:

1. Close the app and restart it: Sometimes, simply closing the app completely and then reopening it can resolve temporary issues.

2. Restart your iPhone: This can refresh the device's memory and might help with app stability.

3. Check for app updates: Go to the App Store, and under the "Updates" tab, ensure that your music app is up to date.

4. Check your iOS version: Sometimes, updating to the latest version of iOS can fix compatibility problems with apps. Go to Settings > General > Software Update to check for updates.

5. Free up storage space: If your device is low on storage, it can cause apps to crash. Check your storage under Settings > General > iPhone Storage and delete any unnecessary files or apps.

Please let me know what app you're using and if you’ve tried any of these steps already!