I'm not sure if I even believe there ever was a 'client list' - why would such a thing exist? In fact, I think we've already seen all the 'files' that we're ever going to see, bearing in mind that there are almost certainly names of victims in there who were minors at the time so this is as it should be.
The problem for Donald is that he was the one who told his supporters that the list existed and that he was going to release it. And for once, they actually seem to care that he lied.