I tested flac file you shared on my Xuelin ihifi1969 and it indeed gives error and won't play. I have maybe (probably) latest firmware 1.08 2017-11-21. So your player is not to blame, it's the file for reason unknown. Most of my flac files are my own cd rips with EAC, with compression level at 5 I believe. No problems with any of those flac files.
Thank you!
I'm not familiar with MAC computers, but in Windows 10 and Lubuntu both card and internal storages show up normally in file browser, like any other type of mass storage device would. Have the player's second screen turned off (lower switch down), when connecting in to computer. I don't know if that really matters, but I think on Windows it didn't show up if switch was turned on. On Lubuntu it shows up no matter the switch position, so I'm not sure what's the case with that. I don't really use interal memory, because I have 128gb card, filled with 96gb of music, and switching between internal memory and card memory isn't that practical. Scanning the card memory takes several minutes so everytime I wanted to switch from internal memory to card memory, I would wait for several minutes in silence. Not practical at all. I use only card memory, and use usb card reader to connect it to computer.
