Twice this year I've found a name I've used in one of my books spending its time in someone else's novels.
To a certain degree this is inevitable, since names are rarely unique. My nephew, for instance, shares his name with a female guardswoman roleplaying character (and my space naga, for that matter). But distinctive or particularly well-known names are ones to treat with care.
It's entirely possible to use established real-world names which happen to feature in books (Hermione or Bella) and not cause a fuss (unless there are other similarities) but even so the reader will bring associations to the name, and may be jarred from your story. And distinctive names unique to or rarely encountered outside a particular novel or series (Rand, Menolly, Severus) are something which will almost always bring negative impacts to the reader/author experience.
In my current cases, my fallback term for magical schools (Arcanum) appears to have most recently shown itself in Patrick Rothfuss' novel. I will probably keep the name unchanged, since it is not nearly so distinctive as something like "Hogwarts". And today I found that the very distinctive surname of one of my main characters is the first name of a character in an extremely well-known series of novels.
Fortunately the spelling is slightly different, and almost everything else nothing alike, so I will also keep this name. But it was a close call. Giving up on a name you've spent a novel with is not an easy task. I can barely imagine how I'd cope if I found out Gandalf and Aragorn were also 'taken'.