Hello, The field PhysicalTrackNumber of media files created by AMT3 is invalid on sourceMob with essences and is absent on masterMob. Our software uses this properties to manage mapping, do you think you can do something about it ? sample dump: Object of Class: SourceMob MobID: { {0x6,0xa,0x2b,0x34,0x1,0x1,0x1, ... 0xa6 } } } Slots: Strong Object Reference