I had to reconfigure a NAS system the other day but unfortunately the previous admin set it to a MTU of 9000.
Guess what happend my system did not support that value at all. I was only capable to selct 9k as Jumbo Frame (means 9014)
So I googled and found:
netsh interface ipv4 set subinterface "LAN" mtu=9000
An interims setup on my Windows 8.1 machine that allowed me instant access to the NAS to reconfigure.
LAN is the name of my interface on my machine. You might change that on yours. Further this is only a quick hack and not persistent.