Can't install Stylecop extension from RU Extensions..

I cant install the "Stylecop by JetBrains" Extension from the Resharper Ultimate Extensions.

The install appears to work, get the usual visual studio bar prompting Resharper extensions have been installed, restart...

I restart, the extension has not been installed, and in the extension list it is shown as still an installable extension rather than installed.

Any logs files I can look at? Anyone know what to try?

Tried fully uninstalling resharper, same happens.

Only happened since upgrade to 2018

Thanks....