Hello Patrizia,
you're right, there is a bug in the Windows beta that prevents the folder to be moved correctly to the final destination - that's why we call it a beta ;-)
Of course we will issue an update as soon as possible, in the meanwhile, you can find the output generated by the preview on this path:
C:\Users\USERNAME\AppData\Roaming\PubCoder\Caches\2.0.0.484\Projects\1\Compiler\SCWebCompiler\18.1.1\C1\web-reader\webapp
Please replace USERNAME with your actual user folder name, also some numbers may vary.
Best Regards,
Angelo