Hi @mducci15
Sorry for any trouble caused. It is not normal for files to suddenly go missing.
Have you tried using a computer to view the files?
We do not have any preferred methods of data recovery as this may vary from SD card manufacturers of the preferred methods for recovering your data. However, you may be able to perform a Google search to find various data recovery options to recover the footage that had been lost. Yet, please do your research on whichever data recovery software is best for you as it may require activation of the software and there may be varying costs.
It is also best not to record any new photos and or videos with the card that had been used. This will overwrite the files that may have been on there to where it would not be possible to recover.
I do recommend to reach out to the SD card manufacturer to further troubleshoot the SD card.
Thanks!
Ej
