How old is your MX-3000? Mine was from late 2004 and consequently had the older proprietary mini-USB port. Mine stopped connecting to the computer and the reason was damage to the port. Take a careful look at the port on the remote to make sure it's not damaged. If it is the only solution is a replacement. I called URC and initially they told me it could be repaired but that turned out to be incorrect. They replaced the unit and I was then able to upoad and download again without problems.