Apple’s release of macOS 10.14 (Mojave) introduced a new privacy protection feature which requires users to allow applications to access protected locations. When you run Toolkit you may be prompted for access to Photos. There should be an accompanying message letting you know why the application wants access to this location as shown in the example below:
If the prompt is not acknowledged, it may disappear after a period of time, defaulting to denying access to the location. It is possible to enable/disable access on a per app basis within the Security & Privacy preference pane.
Click the Apple Icon > System Preferences > Security & Privacy > Privacy tab. Or if you’re on your Mac computer right now click here to open Security & Privacy pane
The preference pane will need to be unlocked by clicking the lock icon in the lower left-hand corner, then entering your credentials. From there you will be able to place a checkmark next to the app to enable access or disable access by removing the checkmark. The application will need to be restarted for the changes to take effect. See macOS Mojave User Guide for additional information.