Lately, for some reason, I became fail preview in the program (RW 6.3.8 and RW 6.4). For example, do some changes on the page, changing the theme or something in the theme itself, but only in watching white blank background. Deleted all settings and cache, but to no avail.
You’ll probably need to provide some more concrete specifics about the issue in order for people to provide specific help.
You could give the URL to the site, screenshots, or even provide the project file if you can – all will help chase down the issue.
Isaiah
Thanks! But what does the site? Speech about the program and Preview it generated pages. The project also does not matter, as is happening in the project you created earlier, and the new, not yet been saved.
Mac OS 10.9.5 and RW 6.4.
I think perhaps there is a bit of a language barrier. Sorry. 
RW 6.4 is very solid version. It works well for many. This problem to me sounds likely to be related to a detail, setting, or preference. Without more info, I’d just be guessing though. Which is not super helpful. Sorry.
Isaiah