Finally got my testfile working.. sorta. Had originally loaded Skyrim.esm + TestMusic.esp in creation kit with no success. Then tried loading Skyrim.esm + Update.esm + TestMusic.esp and got an error message saying something along the lines of "Audio: cannot find music file in hexcode: 01....". Notice that it's hex-code was starting with 01. As greenmachine mentioned earlier, in his previous post, this appearantly refers to the loadorder. So, going into the duplicate of MUSCombat01 that I had made, I readded the .wav file there (both for finale and single file although you probably don't have to). Then I went into the Music Type (duplicate of MUSCombat) I readded it to the list there. Flagged "Abrupt Transition", had no conditions, no other flags. Saved the esp and built a .bsa just for good measure. Hokay - restarted Nexus Mod Manager, removed all other mods in the load order. This left just Skyrim.esm + TestMusic.esp in the loadorder. Now it works. However, if for some reason its not 01 in the loadorder, you will CTD. So its not really a fix since you cannot know for certain that your mod is loaded first. I guess we need to wait for a CK patch. PS: I'm sure there are steps of the above that aren't necessary.