High Frequency Oscillation hurt resistors in Magico A5 crossovers

Strikes me a bit odd for a passive resistor to blow before the tweeter itself, but perhaps they designed it that way on purpose to protect the tweeter -- resistors are usually a lot cheaper to replace than tweeters.  

But, I know nothing about Magico speakers and their crossover design, so the above is just speculation. 

I have no idea why extremely high frequency energy was emitted by the download process, but, Magico's explanation of what happened to the crossover is reasonable.  There is no way it is a failure of the Magico crossover operating under normal circumstances.  A lot of high frequency energy must have gotten through in order for resistors in both speakers to be fried.

I don't know how you have tested the tweeters independently, but, you are fortunate that they survived the ordeal.  In a way, the resistors acted as fuses.

From your experience, updating software while playing the system appears to be something to avoid.  I hope your problem is confined to that situation and it is not a problem waiting to happen again.

Not entirely sure about warranty at this point. Would be nice to know what caused it however?

Wow very unfortunate. Sounds a bit of a lame excuse since music has LOTS of high frequency and a download? You were lucky as others have pointed out the tweeters are ok. 

Actually, music played at any volume that the speaker was designed to handle rarely contains enough high frequency material to damage a tweeter.  

Most often tweeter damage is caused by amp clipping -- the clipped signal basically becomes square waves which generates much more high frequency energy than was present before clipping.  Another culprit from days of old was when one fast-forwarded an open reel recording without muting or reducing the volume. And if an amplifier went bad and started oscillating, that too could damage a tweeter.  

Have to say that I've never seen a program software update generate high frequency noise. Usually the program simply stops running during the update and then restarts after the update is completed. But, then I'm not a computer expert and don't use your particular setup, so its hard to say exactly where the HF noise came from. The OP did say he was listening at "a very moderate" level which seems a polite way of saying it was fairly loud. Maybe the resistors were already pretty hot and it didn't take much to push them over the edge.  

Good luck with your inquiries. It would be interesting to have a more complete answer.