Thanks for the speedy response!
Again, the ideal would be to find a converter that runs on Mac and produces files the Fuze+ can read. And again, one of the oddest things to me is that my old Fuze does play the FLACs from Switch that the Fuze+ doesn’t recognize. The gentleman at SanDisk said this suggested a tag issue.
I’ve spent a fair amount of time poking around online (mostly going in circles, I’m afraid), and I gather that the Fuze+ can be picky about tag formats. Marvin the Martian even posted an example from MP3Tag on the AnythingButiPod forum. But the tag editors I’ve looked at (Switch, Tag, and Winamp) don’t reveal nearly that much about the formats of the tags they produce.
I used the 96000 sampling rate with 8 (best) compression. The original file was 27.4 MB, the Switch output was 13 MB, and the file from Online-Convert.com (audio.online-convert.com, recommended by SanDisk Support) was 8.1 MB.
The Online-Convert output displays this encoder: Lavf55.2.100 Switch’s gives reference libFLAC 1.2.1 20070917
I’d be interested in trying another converter that used Lavf55.2.100, but most converters don’t reveal which encoder they use.