I’ve always used a SDHC card reader to read my 16gb SD card to this point. I had the player turned on and in the “file” program when I connected it to my computer. I discovered that I could read and change files to the card without using the card reader. Have others discovered this? I was surprised and confused.
I don’t have an e250R so I’m not sure what the “file” program is, but almost all players allow for syncing music to an expansion card while the card is in the player, which requires reading/changing/writing files on the card. The player either mounts the card in MSC mode, in which case it is like just another disk drive on your system, or it mounts the card in MTP mode, which also allows direct modification of the card’s contents in Windows Explorer, though possibly more limited than MSC mode.