Just installed Windows v19 x64 Beta 1 on Windows 8.1 x64 (all current updates). I renamed my existing v18 profile folder, to be on the safe side with a first beta and to start with a fresh profile (I'll be more adventurous with later betas.)
First thing I noticed: the Tools-->Options-->Export/Import Options-->Export All Options button does not export any zip file at all, instead an error dialog "No Options could be exported".
If I set up a new Options group that includes everything, then the export to a zip file proceeds as expected; a subsequent entire import of that options file also seems to work.