You renamed the original RECORD folder and then modify the folder name back to RECORD again, it is useless. The device only recognize the recording files in “RECORD” folder which is created by its system automatically, so even if you modify the folder name back to RECORD, it still useless. Please make sure the device disk only have one folder.
Please try to start a new recording, then you will find that there is a another new RECORD folder in disk, and then you need to move your recording files in the modified folder into the system newly created RECORD folder. And delete your renamed folder. So the device can recognize and playback all your existing recording files normally in device.