Why your character stopped feeling real
You're a hundred pages in. The character who used to talk to you in the shower, who had a voice you could hear before you'd written a word of dialogue, has gone quiet. She still moves through your scenes. She still says lines. But something is off, and you can't name it, so you've stopped opening the document.
This isn't writer's block in the usual sense. You know what happens next in the plot. You could outline the rest of the book in an afternoon if someone made you. What's missing is belief: you no longer believe the person doing these things is a person.
If you've stopped opening the file, this is probably why, not because you ran out of story, but because you stopped trusting the person at the center of it. That's fixable in an afternoon. It doesn't require throwing out a hundred pages, and it doesn't mean the book is broken. It means one thing in the draft needs naming, and once you name it, the paralysis usually lifts faster than you'd expect.
The moment a character starts serving the plot instead of themselves
Here's the common cause, and it happens to nearly everyone who writes past the hundred-page mark. Early on, your character had a want. Something specific, something that made every choice legible: she wanted to get out of that town, or prove her father wrong. That want generated scenes. It made her interesting because you knew what she'd fight for.
Somewhere around act two, the plot takes over. You need her in the warehouse at midnight, so she goes to the warehouse at midnight. You need the reveal to land in chapter fourteen, so she suddenly notices a detail she'd have caught in chapter three. Each of these choices is small and defensible on its own. You needed the scene to happen. But stack twenty of them and the character stops making decisions and starts fulfilling assignments. Readers, and writers, feel this before they can explain it. She's not choosing anymore. You are, and you're using her hands.
A five-minute diagnostic that actually tells you something
You don't need a beat sheet or a personality quiz to find where this happened. Pick the scene where you first felt the flatness, or if you can't pinpoint it, pick any scene from the last twenty pages. Then answer two questions honestly, in writing, not in your head.
Scene: [what happens]
1. What does she want right now, in this scene, that has nothing to do with the plot's needs?
2. If the plot required nothing of her here, what would she actually do?
3. Does what she does in the draft match answer 2, or did she do what the outline needed?
If 3 doesn't match 2, that's your flat scene.Run this on three or four scenes and a pattern usually surfaces fast. Maybe she keeps being reasonable when her actual want would make her reckless. Maybe she keeps forgiving people your outline needs forgiven. The flatness was never random. It clusters exactly where the plot needed something her want wouldn't have produced.
The fix isn't a rewrite, it's a negotiation
Once you've found the scenes, you have two honest options. Either change what happens so it's something she'd actually do given her want, or change her want, permanently, so the plot's demand becomes plausible. What you can't do is leave the scene as written and hope nobody notices. Readers already noticed. That's why you're stuck.
This is smaller work than it sounds. Most of these fixes are a paragraph, not a chapter. If she wouldn't walk into the warehouse for the reason you gave her, give her a better reason, one that comes from what she wants, or let her refuse and make the plot bend around that instead. Refusal is usually more interesting than compliance anyway.
The deeper habit worth building is checking a scene against her want before you write it, not after. That's the discipline that keeps a hundred-page draft from drifting the way yours did. It's also, frankly, the difference between writing that feels alive to you and writing that feels like homework, which is usually the real reason the document stopped opening itself.
None of this requires waiting for inspiration to come back. Inspiration isn't what left. What left was a clear line between your character and her want, and that's a craft problem, not a mystery. Fix the line and the voice you used to hear in the shower usually comes back on its own, sometimes within the same sitting.
If you use Chaptered, its character summary card keeps a character's core want, flaw, and voice notes visible while you're drafting, so you can check a scene against them instead of trying to hold it all in memory a hundred pages later.