I have no idea how this worked since “Humanoidd” isn’t a valid child of the player’s character, nor does the player’s character have a sound instance named “Sound” which the instance method “:Destroy()” can be called on, anyway, here is the fixed script for anyone who needs it.
local Players = game:GetService("Players")
local Player = Players.LocalPlayer
local Character = Player.Character or Player.CharacterAdded:Wait()
local Humanoid = Character:WaitForChild("Humanoid")
local Sound1 = Instance.new("Sound")
Sound1.Name = "Walk"
Sound1.Parent = script
Sound1.Looped = true
Sound1.Pitch = .77
Sound1.Volume = .45
Sound1.SoundId = "rbxassetid://190126294"
local Sound2 = Instance.new("Sound")
Sound2.Name = "WalkShoes"
Sound2.Parent = script
Sound2.Looped = true
Sound2.Pitch = .77
Sound2.Volume = 0
Sound2.SoundId = "rbxassetid://311349802"
Humanoid.Running:Connect(function(Speed)
if Speed > 3 then
Sound1:Resume()
Sound2:Resume()
elseif Speed <= 3 then
Sound1:Pause()
Sound2:Pause()
end
end)