When I upgraded to Windows 10, File Explorer worked fine when I was accessing files on my network attached storage device (Western Digital MyCloudEX2Ultra). After updating to Windows 10 Anniversary, when working with subdirectories on the NAS that contained files with long file paths, attempting to sort by "Date Modified" crashed File Explorer. I soon learned that other File Explorer functions also crashed when working with such files in those subdirectories.
After reading comments on this forum and other places, I attempted to enable long file capability in the registry but the entry was no longer present.
I have resorted to reducing the length of my directory titles to attempt to bring the files within the limitations of Windows 10AU, but there are far too many files affected for this to be a permanent solution.
Microsoft needs to fix this issue as soon as possible.