Try wrapping it in a pcall and keep on running that pcall until it doesn’t error. Also put a wait in between, something like this:
local success, errormessage = nil, nil;
repeat
success, errormessage = pcall(function()
button.ViewportFrame.WorldModel.Dummy:WaitForChild("Humanoid"):LoadAnimation(PreviewAnim);
end);
task.wait();
until;
success and errormessage == nilthis post was two years ago 
ngl I dont think they help anymore
I just realized- by saying this, I have started the thread again. How long will this go on??? My bad gang
lol why do you keep necroposting
mb gang i didnt realize this post was about to die again, i didnt read the date of the last message
xd am hav ing diz izsue
eks dee bro so anoying
When does this trigger, because simply adding a:
local rs = game:GetService("RunService")
-- Add this at the start of your second for loop
rs.Heartbeat:Wait()
could fix it. For me whenever I have this issue, adding a load wait works. Especially a heartbeat wait. Even if heartbeat isn’t enough, you can add task.wait(0.5) (or tone it down to 0.1).
Another cause could be parent not being initialized as a result of duplicated, check for that. Though, I highly doubt that’s it, and a load wait would probably be enough.
chat to fix this you just have to parent it to workspace or anything thats descended from workspace before you load the animation
i had a feeling it would be like this as someone previously stated that the object they were trying to animate was in replicated storage.
in my case i was cloning an asset then to weld it, load idle, then set it to character when you have to
set it to character before you load the idle 
I know that this may be a necropost, but I’m getting this error now. I’ve set up a tool.equipped:wait() before loading the animation, and that still didn’t fix it. It works fine the first time the character loads, but respawning makes it refuse to work. I even at one point used a task.wait(3) to test, and THAT didn’t fix it. Also tried heartbeat, stepped, etc. I’m so confused, I just want to throw a snowball. : (
local Tool = script.Parent
local Handle = Tool:WaitForChild("Handle")
local Players = game:GetService("Players")
local Player = Players.LocalPlayer
local Character = Player.Character or Player.CharacterAdded:Wait()
Tool.Equipped:Wait()
local ThrowAnimation = Character:WaitForChild("Humanoid"):WaitForChild("Animator"):LoadAnimation(Tool:WaitForChild("ThrowAnim"))
I’m having this error too, 
there’s most likely a similar block of code here but I made a module for this a while ago and it’s been working fantastically for me.
local module = {}
function module:LoadAnimation(animation:Animation,animator:Animator)
local success, errorMsg = nil, nil
local Animation = nil
local tryCount = 0
repeat
task.wait(1)
success, errorMsg = pcall(function()
Animation = animator:LoadAnimation(animation)
end)
if success == false then
tryCount += 1
warn(errorMsg, "retrying...")
end
until success == true or tryCount == 5
return Animation
end
return module
I made this for a game I was working on and I went to this post and absolutely none of the solutions were working, I remember I did a 30 second yield once and it still gave me the error. I despise this bug, it needs to be fixed.
code might not be the best since I made it a while ago so feel free to make improvements
Just found this error trying to load an animation of a Humanoid that is not in the Workspace.
Once I put him in the workspace and it works fine.
I’ve fixed my issue, I believe I may have a theory as to why this glitch is occurring; the dummy/NPC/Humanoid must be in workspace whilst calling :LoadAnimation() on it, otherwise this error occurs.
I’m not sure why this has to be done intentionally, but anyone who says it needs to be parented is correct. You HAVE to parent it first before it could actually load the animation which is really annoying. I wish the LoadAnimation() function could just do this themselves but no. So yes, essentially you’d have to parent the model of which you are trying to load the animation for BEFORE calling LoadAnimation on your Animator. I have tried doing this in ReplicatedStorage and it seems to be working just fine. You can do workspace too, and probably StarterGui if the model is inside a ViewportFrame.
Can we get this fixed please? It’s quite unpleasant and quite literally breaks my game
Hello developers, now I kinda have found a way to fix the issue.
So first of all, you cannot use :LoadAnimation() on Characters those aren’t parented to workspace
to fix this, I parent my character into somewhere inside workspace
local Plr = game.Players.LocalPlayer
local Char = Plr.Character or Plr.CharacterAdded:Wait()
Char.Parent = workspace
hope this help !
: mostly happens with StarterCharacter&Tools
My NPCs are loaded into workspace before they receive the script that load animations and yet it still happens. I see the error in the analytics, but I can’t find it in the in-game logs or reproduce it in studio.
Roblox engine is just full of problems and unreliable and we need to live with it…
(That’s only over the last 24h)
this was the issue for me too, need to make sure the model is parented to the workspace before any animations are loaded and played
Same here, I explicitly put some lines to check if the NPC is in workspace before calling loadanimation, and if it isn’t i put it in the workspace, but I’m still getting thousands of these errors. Not only that, I also wrap LoadAnimation in a pcall so I honestly do not understand why its not being silenced and still ending up in the error log. The error never happens in studio
Hey! So I never updated the post, but it seems to be coming from roblox internal scripts, I later realized that the “Type” is “Client” and my NPCs runs with a server script, so wasn’t that.
Adding their “Animate” script in StarterCharacterScripts (Copy-Paste the one inside a character) and adding this line at the top of the “playAnimation” function seems to have fixed the issue for me
if not humanoid:IsDescendantOf(workspace) then
return
end