We are using a one-month old XPS 8900, i7 with 16 GB memory, D-Link DNS-323 NAS and Office 2016. Windows 10 Pro v1607 Build 14393.351.
User account "A" is able to access and open Word/Excel files very quickly. No performance issues.
User account "B" struggles to open these files. We see various phases such as "Contacting ... NAS", "Downloading", "Processing" and eventually opens. Closing the file takes several seconds.
I chatted with Microsoft support ... they connected to view the issue and concluded it was "weird". Microsoft will not escalate the issue because the file is not directly on the computer.
As mentioned above, user account "A" works fine!!
Any ideas? Thanks!