server issues with el capital

Hi all,

me and the mrs both took the plunge immediately with the el capitan update only to find we could no longer access our NAS server. was horrible.

in the end we had apple have a go at looking at it via web help all to no avail.

can i ask if anyone else has suffered this problem and if there is a way around it apart from going back to yosemite like we did.

the hardware in question is a macbook pro mid 2014 with 16gb ram and solid state hdd and i7 core processor with integrated iris graphics.

the mrs has a mac mini early 2015 model with 16gb ram and solid state hdd and i7 with iris also.

thanks in advance