Thanks for the screenshots. The file Take0249(0001).wav is really missing then. Can you tell me the firmware version of the uTrack24? We have never seen this problem in uTrack24, there could be something that went wrong when writing to the drive but not detected by the uTrack24. I cannot say for sure. Cymatic does not provide any tools to recover this kind of missing file. Maybe you should have a look at third party tools to see if the file still exists and if you can recover it.
In general, we started seeing some minor problems (including dropouts) when there were more than 150 takes in a single folder. I would recommend you to make a backup of your recordings somewhere else and format the drive again. Try to have not more than 100-150 takes in the /Multitrack folder. We will have a closer look at what really happens when we have 200+ takes in the recording folder and try to find a fix for that.
Regarding the extra take you see, when the pre-recording function is ON, the uTrack24 continuously records audio into its internal buffers. The folder _TempTakeXXXX and the first file inside it are also created and ready to be written. As soon as the record button is pressed, no time is wasted in doing file/folder creation operations. The only operation done is renaming the folder (from _tempTakeXXXX to TakeXXXX) and immediately after that writing to the wave file begins.