NGEN should support explicit path based assembly load
Please add NGEN support for Assembly.LoadFile and Assembly.LoadFrom. For more context see the blog post http://blog.bonggeek.com/2013/12/net-ngen-explicit-loads-and-load.html
Today NGEN images (or native image probing) is supported only in the default load context. That means any mechanism used to load assemblies from an path, e.g. using Assembly.LoadFile do not get NGEN support. For Assembly.LoadFrom it's even weirder, it sometimes work and not on other times. This makes hard to build performant large scale applications that uses loosely coupled plugins that are loaded dynamically
I suggest you to download new Long Path Tool software that simply allows you to work easily on Long Path files.