Objects are trying to be loaded during a domain backup.

I just upgraded from 2020.3.30f1 to 2020.3.33f1 and now I get this error:

Objects are trying to be loaded during a domain backup. This is not allowed as it will lead to undefined behaviour!

The game still runs but I'm not sure why I am getting this error.

Anyone else run into this?

 

Yeah I got the same 4 errors in a row after updating from 2021.2.9 to 2021.2.18. Someone at Unity made a whoopsie...

To fix this you'll probably have to delete your Library folder and reopen (meaning a lengthy reparse of) the entire project. That's how I fixed it on my end.

 

Ok, thanks for your reply.

 

Ok well I did try deleting my library and let Unity rebuild it. But I am still have the same issue. It was worth a try I guess.

 

You're right, I can confirm that rebuilding the library will only fix the issue for a while but the errors come back.

Now we can only hope there's someone at Unity able (or willing) to fix this. *sigh*

 

Same problem here. Sad we don't have a more detailled log.

 

Same problem here, after upgrading from 2020.3.30f1 to 2020.3.32f1. It happens to everyone in my company that also upgraded.

 

I have the same issue. It called by Odin Serializer.

 

If you're getting this from the Odin plugin they have a hotfix available to remedy this. Should be able to ask for it in their Discord group.

 

Same issue, I found out that deleting all assets of a custom ScriptableObject class resulted in less error messages. I'm wondering if it's because of some AssetDatabase or Resources loading instructions which are called from OnBeforeSerialization.

The good point is that Unity doesn't crashes anymore (well almost), so maybe this error is Unity telling us it prevented some unsafe code from executing ?

 

Just upgraded to 2021.3 LTS, got the same thing, but no useful information to what is causing it.

 

Are you using Odin Inspector at all?

Otherwise the issue they discovered was that in some versions of Unity, not others, calling the prefab API during serialisation is a no go and throwing this error.

 

I just upgraded to the recent 2020 LTS and am now getting this on 2020.3.33f1, not using Odin Inspector. Log just spams:

Code (csharp):

1. Objects are trying to be loaded during a domain backup. This is not allowed as it will lead to undefined behaviour!
2.  
3. UnityEditor.Graphing.GraphObject:OnBeforeSerialize ()

 

I'm using odin inspector and got it after updating to 2021.3LTS so there's definitely something wrong here

 

Same here.

 

A fix for this in Odin Inspector is on its way to the Asset Store, we're just waiting for it to get approved. It's available for download on the website now though.

 

I'm having this problem in something other than Odin Inspector. Can you please tell me what the fix is so I can apply it to my code? Thanks!

 

I was not the one who did the fix, but reading off the changelog :

I think it was because ISerializationCallbackReciever was getting hit during an AssemblyReload event where utilizing the Prefab API (and various other API's I Imagine) is now illegal. So the fix was to detect an assembly reload was occurring, and not do the prefab stuff in such cases.

 

As a LTS the quality is terrible, i'm having all kinds of small bugs and i'm too busy to search all of them or open a bug report.

Unity team should really rethink this LTS releases, i already regret having updated my project, 2020.3 was way too stable and less buggy.

I'm getting this same messages, but i'm not using anything serialization related, this 100% a editor bug:
"Objects are trying to be loaded during a domain backup. This is not allowed as it will lead to undefined behaviour!

UnityEditor.Graphing.GraphObject:OnBeforeSerialize ()"

 

The fun part is the trailer stating "stability proven" and then getting 2 crashes just renaming folders.

Regarding the topic, Odin Inspector just got the 3.0.13 update (on the store) with the fix for this issue.

 

I did a fix by deleting Shadergraph in package manager Im my case it was in Shader graph, may to fix this is just compile your shadergraph files into a normal shader and after delete shadergraph maybe is a bug in shadergraph. This worked for me, I am using 2021.3.0f1

 

The "Remove" button of the Shader Graph in package manager is in gray color and cannot be clicked.

 

Yes, using Odin, even after updating Odin for the latest fix, I am still getting this error.

 

2021.3? what RP? URP, HDRP or legacy (as a previous user mentioned Shader Graph)?

 

Closing the ShaderGraph window has removed the error for me (at least temporarily).

 

To anyone approaching this issue and trying the above solutions:

My solution to fix the error was an extremely small mistake I missed in a custom script.
I discovered I placed the Update[ ] portion of the script before the Start [ ] portion.
Reversing the two and placing Start [ ] in its usual first position fixed the issue.

Hopefully everyone else has the same easy fix I did. If not, then good luck. ^_^

 

I can safety say that will have zero effect on this issue at hand. How you order Unity messages in a script file, and in fact how you order any of your method declarations in a class/struct won't have an effect on anything besides maybe Reflection based matters.

 

The order of functions in your source doesn't make any difference in C#.

- - -

I'm getting the issue as well, and can confirm that in my case it's because I'm calling PrefabUtility stuff in OnBeforeDeserialize(), i.e. as a part of ISerializationCallbackReceiver.

 

I should expand on that. It was definitely the cause of at least some of the errors. Unfortunately they don't all have a stack trace associated with them, and there are remaining cases I've not yet found the cause of.

 

For me it was launching the game with a shadergraph editor window open. (2021.2.17f1)

Anecdotally, the shadergraph window has crashed Unity more times in the few months I've been using it than all other causes in the last decade put together.

 

Was that causing the ones without stacktraces, or just in general?

 

There was no detailed stacktrace, but it did mention shadergraph in a line under the error message. If I can get it to happen again I'll make a note of the details. Closing the shadergraph window stopped all the errors.

 

latest LTS is buggy

 

Yep, same here latest LTS 2021, and not using Odin

 

I have the same bug. I'm using Unity 2021.3.1f1.

Objects are trying to be loaded during a domain backup. This is not allowed as it will lead to undefined behaviour!



UnityEditor.Graphing.GraphObject:OnBeforeSerialize ()

 

yay me too.

2021.3.1f1

No odin.

 

Same here with 2020.3.33f1 LTS, hundreds of error messages in my project that I need to clear all the time.When I doubleclick on the error it takes me to an OnBeforeSerialize() event in the code.

Sounds real easy to fix, any chance anyone at Unity Technologies can take notice at least? We're talking about a LTS version...

 

Yes, this is the most shocking part. These bugs appear in a LTS version of Unity. I choose this version for a new project just to find out it still spams bugs. Very very annoying and unsatisfying to work with ...

 

Just ran into this today after I deleted some FBX files containing animations that I decided not to use. Deleted maybe 15 files hit play and bam.

I'm using git, so closed the editor, then I git reset to head (undoing the delete), reopened editor and no issues.

I also tried deleting the files with the editor closed and manually from disk but alas reopening the editor and hitting play brought them back.

 

I just went through these files 1 at a time hitting play each time I deleted 1 and I worked it down to 3 specific FBX files which are somehow causing this issue for me. I can move them within the project, but if I delete them, blamo. /shrug

 

The thing is, my project generates meshes at runtime, so I have no fbx files in my project at all. So this might be not the main reason why this bug happens.

 

in my case clicking on the error takes me straight to the "culprit" script (simply happens because there is an ObBeforeSerialize event).

I rolled back to 2020.3.30 until this is solved. Great LTS support, Unity!

 

Seems to be solved in Unity 2021.3.3f1

 

So I am using Unity 2020.3.33f1 and found that I got this error because of an open shader graph window on my second monitor. I'm 99% sure this wont help any of you but I fixed it by closing and reopening the window.

 

Have been using 2020.3.0f1 until now and suddenly got the error (four times in a row at that) after opening a Shadergraph window one time. Closed the window, error stayed. Opened a VFXGraph Window, error stayed. Closed all windows, error stays the same. Restarted Unity, nothing changed. Restarted the PC - same result. Installed 2020.3.3f1, opened the project in there, did not touch any Shader Graph windows - erros greeted me again. Tried again with opening windows, closing windows, restarting Unity as well as restarting the PC, nothing changed, erros kept staying there. I do not use Odin in this project and I am out of ideas by now.

Update: Got it to work (somewhat) again thanks to a friend. Went to Edit->Project Settings->Editor and enabled Enter Play Mode Settings->Enter play Mode Options. The two below that stayed toggled off. It works now as long as I keep this enabled.

Update2: Nope, suddenly those bugs just multiply while in Editor mode. I can start the game without errors, though?

 

Can we have a statement from Unity if this bug is fixed and if so, which version?

 

100% I'm rolling back to 2020 LTS.

 

Yeah I'm having this problem too. The solution is to switch to unreal.

 

Having the issue too in 2021.2.19f1, all without stack trace. It would be nice to get stack traces.