I got it to do a local compile using SdFat 1.0.15 and still had the same issues as before. So I tried using WiFi.off() before playing files and then set up the loop() to play all fifteen files. It played all 15 without a hitch and did so three times in a row. The fourth time it stopped playing after the eleventh file but the staus led continued breathing white. That constitutes a HUGE improvement and I believe the hitch on the 11th file may be due to my own coding problem. I will hopefully fix that and then go for four reps of a full set of 30 tracks with bitrates ranging from 128k to 320k. If they play without a hitch then I will need to look into what events are being generated and hopefully find the one that is causing the lockup. I looked at issues for the standard Adafruit 1053 library and it seems that have also encountered some issues, so I will look into their possible solutions. One mentioned increasing the buffer size.