macOS Finder directory listing slow with QNAP NAS

Problem

Accessing a QNAP network attached storage (NAS) file directory from macOS Finder could take 15-30 seconds.

Solution

1.  in Finder, Open the root level of share
2.  click View, and uncheck Show Icon Preview.   Then click Use as Defaults

Rational

macOS Sierra (and earlier versions) is checking each file and over a slower network link this can take a while if there are a number of files.  In a case it went from 15 seconds to < 1 second.   Credit