The general rule with ASIO is that only one application can be talking over ASIO at the same time. It is OK to have multiple applications installed that use ASIO. You'll just run into problems if you try to run two of them at the same time. There is no problem having both MC 12 and MC 13 installed with both configured to use ASIO. Just don't run both MC 12 and MC 13 at the same time. Only one of them will get access to the ASIO interface.
Keep in mind that ASIO was designed to provide a low latency sound path for professional audio recording. The fact that it bypasses kmixer and provides better sound for audiophiles is a side effect and not its purpose. It wasn't designed for easy plug and play for the typical consumer. It was designed for professional audio where engineers and musicians are used to complexity.
I have zero experience with asio4all. I use an M-Audio FW-410 that has its own native ASIO driver provided by M-Audio. I don't have a need for asio4all. Can't help you on your specific asio4all configuration problems.
Well I probably am lumping Asio and Asioforall together here as they are used together in my system but on day 2, I seemed to have solved my problem by only having Asio/Asioforall assigned to only 1 player. I just opened up MC13 and fired up the player's Radio feature and Asioforall's icon popped up as it should, the M-audio sound card was shut off and the USB DAC was on,,, no issues whatsoever. If i'm the 1st one to have runned into this Asio/Asioforall problem after purchasing MC13, well I just hope there's less headaches for the next guy.
I will say that I do run both Players together a lot as I'm constantly downloading albums, storing them on separate hard drives for backup but I need ti update the MC library's before doing so, things like Gendre and sometimes the album covers won't automatically download so both Players (12/13) need to be open for this reason. I only need 1 Player for music playback so there's no reason to have them both setup for Asio/Asioforall. Changing the Playback Option settings to DirectSound on 1 player seems to have solved my issues, so indirectly speaking, my faulting the MC13 download purchase led to my Asio problems even tho it was my actual setup of Playback Options was the cause. Looks like my problems are past me now and this'll be my last post,,,, til the next time.
Cheers,
Robin