I thought I'd share for others who may have this issue.

I was doing an update, when it was interrupted and got this issue. One the remote screen was displayed the model MX-890 and at the top was Unable to find system files. It would fail when I attempt to re-upload the file.

I saw another post that said the remote was dead but I reached out to Support and they provided a bootloader step and I was able to restore the remote.

To do a bootloader:
Take out battery, press and hold Power and Mute buttons and while holding them down, put the batteries back in. Keep holding the two buttons for a minute or so or until you see a bar going across the top of the screen.

For me, the message was at the bottom. Still shows unable to find system files but this time i was able to upload my file.