On another page of my Web site (not this help site), I mention that I think that there are some cases where one should know how the clock works, not just how to tell time. So that's why rather than take the "if your document is doing this, then here is the reason" approach, I thought it might be better to explain pagination in general and describe why things work as they do.
blank page A page that does not contain body content. It may have only a header and footer, for example.
white page A page that is completely white. And I do mean completely; no headers, footers, nada. White.
double-sided document A document that is set up (Format > Page Layout > Pagination) to be double-sided. Printing on both sides of the paper in two passes or by printing to a duplex printer doth not a double-sided document make (it's just a single-sided document printed on both sides of the paper).
duplex printer A printer that has the capability of automatically printing a double-sided document. Flipping a stack of paper over and ramming it back into a simplex printer doth not a duplex printer make.
If you are printing a book from Frame to a duplex printer and you get unexpected white pages, there may not be any way around it, even if the book's files are set up to start "on next available side."
The reason you may be getting white pages is because the Frame book is really just a bunch of distinct files (or printer jobs) sent one right after the other (indeed, another person's job can get squeezed in quite easily). The printer cannot take the first page of one job and slap it on the back of the job before, so if the last page of the file ends up on a top (right) side of the paper, Frame has no choice but to eject the page (with a white back side) and then start the next job.
The "fix" is to create a PDF of the file and print that instead.
When you create a double-sided document, Frame cannot simply leave a chapter with a nonexisting page. For example, if chapter 4 ends on page 29 and chapter 5 is set to start on the next right page (which would be 31), there has to be a 30 -- it can't just "not be there." If Frame has to add page 30 automatically, then the only place it can get it (automatically) is from the default L/R master pages . . . and these, probably, have a header and/or a footer.
The "fix" -- if you really want a true white page -- is to add a white custom master page and apply it to the back of the last recto page. Another fix, which is sloppy, but it works in an emergency, is to draw white boxes over the items on the page.
But note that I would suggest you never use white pages, because the reader can never be 100% assured that the page is supposed to be blank. After all, errors at the photocopier are known to happen, right? Instead of a white page, leave the header/footer as is and/or use something like "this page intentionally left blank."
These occur because the next chapter starts on a recto page and the problem chapter also ends on a recto page. If it's a double-sided document, Frame is simply doing what it has to do -- add a blank page to the end of the chapter.
Sometimes you get a page that can't be deleted using Frame's "remove blank pages when saving" feature.
The body text has extra carriage returns that run long. Remove the returns.
There is a paragraph that's set to "top of page" but it's blank. Delete it.
There is an invisible graphic floating on the page (these are easy to accidentally create using the text tool). Find the item and delete it, or just delete the page manually.
Frame has detected a change to the text frame (if you've nudged it, for example). Delete the page manually.
The page has had a custom master page applied to it. Delete it manually. If it comes back, apply the appropriate default regular L/R master to it, update the book, then delete it.