Right after updating to Firmware v.64, my SanDisk is showing "Disk Error" on the unit. I then tried to format it, which it said was successful. But same error after reformatting. Also, SanDisk is no longer detected on the Mac. This is the same SanDisk I've used successfully for 9 mos. Before replacing it, has the unit possibly corrupted it via v.64? If so, is this corruption reversible? Thanks for your insight.