Thanks...
 

...yeah, I suspected that it was the burned copy that was causing issues, I'm going to try a better brand DVDs and see what happens.


I was just surprised that after upgrading the SW in the MK4 to v.31 the lock-ups caused a "total failure" of the SatNav
With SW v.29.1 in the MK4 the lock-ups only made the the SatNav "freeze up" from time to time.

But at least "re-setting" still works fine and the SatNav comes back to life.

Thanks for all the help and replies!

It looks like the whole mechanism would be easier to replace than just the laser, but the laser by itself is obviously cheaper. Is it very difficult to make either of these replacements?

Mechanism: very simple

Laser: Experience required

Revisiting this issue, 05 MKIV. New v31 and nav update and no problem for a few thousand miles. Then, like others, funny little freezes that I could cure at first by switching modes, then only by turning ignition of and on at stop lights, then I needed to eject and re-insert the cd. Finally, nothing worked and it was totally locked no matter what.

The cure? Went to In N Out Burger at a busy time. Gave it that quiet time it needed and worked fine. Good thing I didn't go through the drive-thru lane.

I would guess that this successful reboot indicates that the laser is ok and the aftermart map disk is good, that occasional problems must be inherent and not preventable? Or, am I wrong there?

A reset button would be better, but BMW probably thought that would send the wrong message...