Thanks for the advice - much appreciated. Before actually checking out the links you provided, your post got me thinking.
What I believe was the problem (not sure, but once I did the following, it worked), when I used the Easus partitioning & formatting tool, the 64gb sdcard showed up with two partitions - a 16mb (first partition) and the rest as the 2nd partition. This kept happening no matter what tool I used to format the drive (including the one at sdcard.org). I couldn’t enlarge the 2nd partition to “gobble up” the first (so as to have 1 partition), but finally realized (duh) that by deleting the larger 2nd partition, I could enlarge the 1st 16mb partition to consume the entire drive. Once I did this, then formatted FAT32, the sdcard was immediately recognized in my Clip Zip.
So basically, I used a USB writer for SD Cards (including SDXC) to format the card using the Easus tool, AFTER I deleted the 2nd partition and enlarged the 1st partition. Something so simple.
Thanks for your help. Now I have to see if the 6000 file limit I keep seeing is truly the limit with this revision as a reason for the 64gb (instead of existing 32gb) card is due to the number of files I have.