As stated by Dobby in The Order of the Phoenix

‘Because [the Room of Requirement] is a room that a person can only enter,’ said Dobby seriously, ‘when they have real need of it’

Order of the Phoenix - page 343 - Bloomsbury - chapter 18, "Dumbledore's Army"

And as stated in the question Could a Muggle access to the Room of Requirement ?, Muggles can have access to the Room of Requirement.

My question is, when in the movie, some students enter in the Room of Requirement and Filch follows them, the door changes little by little and Filch opens it to see some cleaning stuff. Why didn't the Room of Requirement stay still because what Filch needed the most is to find the students ?

  • 6
    Maybe because the students “didn’t want to be found”?
    – Shreedhar
    Aug 8, 2019 at 7:59
  • 5
    Apparently it can only be one thing at a time. So if someone's in there, it doesn't open up.
    – Möoz
    Aug 8, 2019 at 8:13
  • 1
    @Möoz But it doesn't have to be two different things, Filch wants the same room, the one with the student. And moreover, it opens as a second Room of Requirement with the cleaning stuff.
    – TinyDoowy
    Aug 8, 2019 at 8:25
  • 8
    You do understand: Want != Need. Aug 8, 2019 at 20:17
  • 1
    What about Filch's ... lousy prowess at magic?
    – TimSparrow
    Aug 8, 2019 at 20:49

2 Answers 2


As explained in Chapter Twenty-One of Half-Blood Prince, needing to catch someone using the room doesn’t work:

“Dobby, have you managed to get in to have a look at what Malfoy’s doing?” said Harry eagerly.

“No, Harry Potter, that is impossible,” said Dobby.

“No, it’s not,” said Harry at once. “Malfoy got into our headquarters there last year, so I’ll be able to get in and spy on him, no problem.”

“But I don’t think you will, Harry,” said Hermione slowly. “Malfoy already knew exactly how we were using the room, didn’t he, because that stupid Marietta had blabbed. He needed the room to become the headquarters of the D.A., so it did. But you don’t know what the room becomes when Malfoy goes in there, so you don’t know what to ask it to transform into.”

According to this, if Filch had been trying to get into the DA headquarters it would have worked, but simply trying to catch the students wouldn’t.

In fact, in the book version of Order of the Phoenix (Chapter Twenty-Seven) Umbridge’s people did gain access to the headquarters:

I have all their names here, Miss Parkinson ran into the Room of Requirement for me to see if they had left anything behind. . . . We needed evidence and the room provided . . .”

  • Looks like a good answer to me and consistent, thanks a lot
    – TinyDoowy
    Aug 8, 2019 at 13:40

Suppose that Filch wants "the room that the students are in". Now, if the students want Filch not to see them, then there is a conflict between the two.

However, if the Students just want the entrance to be blocked by a cupboard of cleaning supplies, then Filch can access the room without issue - however, there are walls blocking his view of the students:
Image of a Room-within-a-Room (of Requirement)

Like this, there is technically no conflict between the two requirements - both are fulfilled by one configuration.

  • 1
    @TinyDoowy Perhaps Umbridge wanted to actually see the students, not just the Room they were using? Aug 8, 2019 at 9:07
  • 1
    Possibly because Umbridge had been briefed by a Dumbledore's army insider on the nature of the room, and knew what she had to do to overcome the obstacle. She's also considerably smarter than Filch.
    – tbrookside
    Aug 8, 2019 at 12:47
  • 2
    The cleaning supplies cupboard is what the Room of Requirement originally was. 'It's bizarre,' said Fred, frowning around at it. 'We once hid from Filch in here, remember, George? But it was just a broom cupboard then.' I don't really see where you're getting this weird theory of the students putting a cleaning-supply closet there...
    – user112267
    Aug 8, 2019 at 13:25
  • 4
    @Voldemort'sWrath They needed a broom cupboard to hide from Filch in. They found something that fitted their Requirement. Likewise, when Dumbledore found it, it was a large room full of chamberpots. Is that what it originally was? Aug 8, 2019 at 14:07
  • 2
    Upvote for including Mrs. Norris the cat.
    – Jane Panda
    Aug 9, 2019 at 16:30

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