My new MicroSD card arrived, and it seems to be working. At least it's doing more than the Sad Disc ever did--all my music is in place and recognized. We'll see if that holds up. [Edit--Sad Disc should have been San Disc, but I'll leave it because it fits.]
Amazon.com : Samsung 32GB MicroSD HC Plus Class 10 UHS-1 48mb/s MB-MPBGB Ultra Fast Speed Memory Card with SoCal Trade, Inc. Memory Card Reader : Computers & Accessories
This one came with a USB thumb drive type adaptor, rather than the SD adaptor the San Disc product came with. I don't know if it's the different connector on my PC, but the transfer speed was much more stable with this card. The other one varied about 75% when attempting to copy files. This one probably didn't vary 5%.