Honestly, I always assume these "scandals" are B.S. until proven otherwise. In the case of Peter Schweizer's "Clinton Cash", my skepticism paid off. By the way, it seems clear that the previous Clinton "scandal" I questioned was also connected to this book:

Peter Schweizer's Clinton Cash reportedly does not prove its speculative attacks on the Clintons and even relies on a hoax press release to support a claim, according to ThinkProgress.

Clinton Cash will be released on May 5, and media reports have already hyped the book's supposed revelations about connections between Hillary Clinton's time as secretary of state, donations to the Clinton Foundation, and paid speeches given by the Clintons.

According to ThinkProgress, which obtained an advance copy of the book, "Schweizer makes clear that he does not intend to present a smoking gun":

Schweizer makes clear that he does not intend to present a smoking gun, despite the media speculation. The book relies heavily on timing, stitching together the dates of donations to the Clinton Foundation and Bill Clinton's speaking fees with actions by the State Department.

Schweizer explains he cannot prove the allegations, leaving that up to investigative journalists and possibly law enforcement. "Short of someone involved coming forward to give sworn testimony, we don't know what might or might not have been said in private conversations, the exact nature of the transition, or why people in power make the decision they do," he writes. Later, he concludes, "We cannot ultimately know what goes on in their minds and ultimately provide the links between the money they took and the benefits that subsequently accrued to themselves, their friends, and their associates."

ThinkProgress details several of Schweizer's claims, and highlights one major error already found in the book. According to the site, Schweizer at one point uses a press release to bolster one of his many speculative claims, citing it to suggest there may have been a link between a private company that was paying Bill Clinton for speeches (and which supposedly issued the press release) and a State Department report released when Hillary Clinton was secretary. However, ThinkProgress notes, the press release Schweizer cites was revealed as a hoax back in 2013.