I have a new install of XDK on my Mac running 10.12.6. When I click the Live Preview button for the index.html file in a new project, the button appears to do nothing. If I hover over it, it just says "Live Preview: Connecting..."
I have Chrome installed, but I use Firefox as my default browser. I've tried restarting XDK, and it didn't help.
If you are unable to make that feature work in the XDK, please use Brackets directly. See this link > https://github.com/adobe/brackets/wiki/How-to-Use-Brackets#live-preview < and search for "Alternatives to the Retired Live Development Feature" in the XDK release notes > https://software.intel.com/en-us/xdk/docs/release-notes-information-intel-xdk < for more details.