I have exact the same problem!!! This seems to be a long lasting problem in Vegas.... and not repaired yet!!! Very disappointing...
Vegas does not suddenly open. I have been forced recently (by Microsoft) to run the latest windows (WIN 10 Pro N 64-bit) updates. Additionally I have installed an ASIO driver to be able to input and output from my Behringer mixes via USB (ASIO4ALL). All other audio applications (Adobe audition, Audacity, etc.) and video NLE's (Davinci resolve, Edius) works without problems, only VEGAS derails during loading the ASIO driver.
This is an repeated indication that VEGAS is still a very shaky and brittle piece of software. The repeated feel to be a guinea pig for their software experiments, and paying for it (both money and precious time) is sooooo frustrating. Note very professional. I am NOT even considering V16 before 15 works as promised. Needless to say, I have other problems that I will not mention here in this thread.
Deleting the ASIO driver next just for the sake of Vegas... lets see what happens…