Ok just want to update.
I went to the launcher and made these changes to the engine install for Preview 1.
The second image was a preference thing as really all I’ll ever potentially do mobile dev on is Android.
Doing this however, made changes to the installation which may have added or fixed some things that weren’t included in the installer 
Basically meant that deleting the Win64 folder in the {YourProject}/Binaries and letting the engine rebuild them fixed this issue for me.
However I think some plugins that worked for EA2 don’t work currently for preview 1. DLSS for example is broken for me, so will need to wait on a update from NVIDIA on that.
Mileage may vary, but try disabling plugins if you can and deleting binaries so that the engine will rerbuild them.