There seems to possibly be some instability in the code used for this feature.
I've been using Build 25 for a while ( because I have a number of CUE files, and have had too much other work over the past weeks to deal with fallout from the major CUE rewrite, so I put it off ).
I've had more spare time recently, and updated to 70->73->74.
I added [Playlist Remaining Time] to my player display.
Meanwhile, every morning for the past several years, I have a batch file start MediaCenter and it plays a long (random) playlist of music, suitable for starting the day.
Since I upgraded to 74, every morning the playlist stops playing - after playing a few songs - because it is hanging with white screen and hourglass pointer.
I went back to 25 and everything worked fine for hours.
I thought that maybe the fix in 78->79 might fix this, but when I tried 79, same problem.
So I suspected the new SRC high precision code, and so I tried going back to 66 (before the SRC change)... same problem.
Then on a hunch, I tried 61... and it worked fine for several hours.
Continuing my hunch, I removed [Playlist Remaining Time] from the my Player Display, and then updated to 79... and it has worked fine now ( for longer than it took for the problem to appear previously ).
So, there seems to be something in its code that can cause MC20 to hang (either computing the value, or displaying it).
If and when someone looks at that, also consider changing it to the same format as [Remaining Time] - i.e. an intenger number of seconds.
Thanks !