Q1: I used an Apple Mac to copy the sound files to the onboard flash memory. Now not all of the buttons play a sound when activated

A1:   We found that some versions of the MacBook hide some of the files when they are copied to the onboard flash memory. Solution is to reformat the onboard flash memory, using a Windows computer and then copy the sound files to the onboard flash memory using a Windows computer. 

Q2: I used windows 10 to save the files to the unit. Now the buttons don't play a sound when activated

A2:    This version of windows hides the files from the root directory of the flash memory. Solution: create folders and name them 01, 02, 03 through 10 in the flash memory and on the PC, and put the sound file 001.mp3 into folder 01, 002.mp3 into folder 02, 003.mp3 into folder 03, …010.mp3 into folder 10 respectively.