Hogwarts Legacy spells: Every spell you can learn
Hogwarts Legacy Merlin trials: How to solve the trials
Hogwarts Legacy Room of Requirement: How to get in
Hogwarts Legacy Demiguise statues: Unlocking Alohomora
Hogwarts Legacy eye chests: How to crack them open
Hogwarts Legacy broom: How to take flight
The Hogwarts Legacy Clock Tower puzzle is just one of the many secrets concealed in the School of Witchcraft and Wizardry, but like the torch puzzle, it's easy to pass by if you're busy doing quests. However, if you're willing to take the time, you can get yourself some nice new gear and items for the Room of Requirement.
If you're just starting out, you might want to know how to solve the Ghost of Our Love treasure map, or how to get a broom so you can start flying. Otherwise, here's how to solve the Hogwarts Legacy Clock Tower puzzle and open those doors that keep slamming shut.
How to open the Clock Tower symbol doors
There are four doors with different symbols scattered throughout the Clock Tower, though you can only access the Unicorn symbol door in the Clock Tower Courtyard at first. You'll notice that the bars protecting the door will start to open, but then it'll suddenly slam shut so you can't get in. The secret to opening these symbol doors is the spell Arresto Momentum; a slowing spell you get from Madam Kogawa's second assignment after you meet her in the Flying Class quest.
You won't be casting it on the door, though. If you look at the Clock Tower floor you'll see a set of four symbols that match the doors located throughout the tower, with the pendulum swinging over each of them. What you need to do is cast Arresto Momentum on the pendulum as it swings over the door symbol you want to open. Rather than slamming shut, the door will open fully so you can get the treasure inside.
The other three symbol doors are accessible once you get Alohomora from Gladwin Moon's "The Caretaker's Lunar Lament" quest when the season shifts to Autumn. You can get to the upper Clock Tower through the Faculty Tower or through the left level one locked door in the courtyard itself.