This is because HumanoidDescriptions include the emote info, although maybe the error message is wrong here. You can fix this by copying over the emote info from the old description into the new description.
local Players = game:GetService("Players")
local function PlayerAdded(player)
local function CharacterAdded(character)
local humanoid = character:WaitForChild("Humanoid")
local oldDescription = humanoid:GetAppliedDescription()
local oldEmotes = oldDescription:GetEmotes()
local oldEquippedEmotes = oldDescription:GetEquippedEmotes()
local newDescription = Players:GetHumanoidDescriptionFromUserId(1)
newDescription:SetEmotes(oldEmotes)
newDescription:SetEquippedEmotes(oldEquippedEmotes)
humanoid:ApplyDescription(newDescription)
end
CharacterAdded(player.Character or player.CharacterAdded:Wait())
player.CharacterAdded:Connect(CharacterAdded)
end
for _,player in next, Players:GetPlayers() do
PlayerAdded(player)
end
Players.PlayerAdded:Connect(PlayerAdded)
Thanks for the update. The user-presented error message was misleading, perhaps it should say that no emotes are equipped for the current outfit or something.