Interesting follow-up.

I had the problem happen again recently. I was driving home, talking on the cell phone, and I'd had the player in standby mode. The player had booted into standby mode, since it had been in standby mode in the office.

I finished the phone conversation, woke the player, and it started playing some music. After only a few bars of the song, it did that freeze. Visuals froze, music stopped. Note that the time-dither effect of the visuals was still running, but the visuals didn't "move".

No error messages on the screen at all.

It's possible that the error happened when it was trying to fill the cache, and therefore it happened when the player was booted in standby mode, and therefore not visible on the deactivated VFD display. Sigh.

I tried something, too. I tried pressing down-down-down to get it to reshuffle a new playlist, and it gave me the hourglass and then locked up the user interface. I couldn't press/hold the top button to put it into standby any more. However when I got home and shut off the ignition, it correctly went into standby. When I plugged the player back in indoors, it resumed the playlist it had been playing prior to my down-down-down attempt. (In other words, the down-down-down thing did nothing at all to it.)