Can't update to 3.3.1.11

Hi,

I’m running 3.1.9 and want to update to 3.3.1.11 in the hope it will solve the appalling sync performance but everytime I try and “Install and Restart” MN3 it closes but never updates… I’ve tried restarting but it will download but not install.
Honestly, this software is great but the support and performance is far too poor.

Can someone please help?!

Jim