In macOS 10.14 or newer, PhoneView needs special permission to access the iTunes backup folder. To give PhoneView access:
- Open the Security & Privacy panel in System Preferences.
- Pick the Privacy tab.
- Click the padlock icon to make changes, and enter your Mac's admin password when prompted.
- Pick the Full Disk Access section. (You may need to scroll down in the list in the left-hand sidebar.)
- Drag the PhoneView app from your Applications folder into the list of allowed apps.