There is a description how to get telemetry from Mantis Q:
For the Android user: Open your File/Storage manager. Navigate to: /storage/sdcard0/YuneecPilot/FlightLog. Select all files, then select Compress and create a name that includes the date. For iOS users: Open iTunes on the PC. Attach iPhone/iPad. Open File Sharing. Select Yuneec Pilot...
yuneecpilots.com
The file names are somthing like "yuneec_2019_05_21_21_33_0.log" or "Sensor_2018_11_22_18_44_08". it depends on firmware version and what device you have used ios or android.
If you found those files copy it to a new directory on you PC. Then select this directory as FlightLog directory in Q500log2kml. Make sure that in Settings > Data conversion the checkbox Flight path from PX4 sensor is checked. On the left side all flight number are listed. Usually it the last number (contains date/time) that is in question. If you select this numer automatically a KML file for this flight will be generated in the same directory as the telemetry files are. Click on the KML-file to see you flight path in GoogleEarth.
In AppLog at the very end you also get GoogleMaps link for start and last coordinate. This is the poit where can start to search your drone.
In case of any further questions don't hesitate to ask.
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PS: It would be good to create an new thread for a new incident in order to make it easier for others with similat problems to find and understand what happened.