Resolved Updating to 2020.2.4f1 messed up all my prefabs!

To the left, the prefab when I open it in isolation.
To the right the prefab in the scene and in the inspector when selecting it in the Project Explorer.

Notice how the values are all different but not marked as such? Reverting them doesn't do anything.
This appeared when updating from 2020.2.3f1 to 2020.2.4f1 on all of my prefabs.

I noticed it's only the case with values from C# scripts.

 

Reimport the prefabs fixed it.

 

I'm also suffering greatly from this issue at the moment.

There is some thing strange going on with nested prefabs.

I can confirm that even if you fix the prefabs in isolation, they become unlinked once placed / instantiated in a scene. In some case I have prefabs with links to scriptable objects that are also broken. It makes no sense.

WTF Unity? You broke my entire game with this random reference breaking "feature".

 

I'm sorry you've had this issue. Please consider using source control in order to guard and protect your hard-earned work.

Personally I use git because it is free and there are tons of tutorials out there to help you set it up.

Here's how I use git in one of my games, Jetpack Kurt:

https://forum.unity.com/threads/2-steps-backwards.965048/#post-6282497

Using fine-grained source control as you work to refine your engineering:

https://forum.unity.com/threads/whe...grammer-example-in-text.1048739/#post-6783740

Share/Sharing source code between projects:

https://forum.unity.com/threads/your-techniques-to-share-code-between-projects.575959/#post-3835837

 

I just got the same issue updating from 2020.2.2f1 to 2020.2.4f1. I'll try going to 2020.2.3f1 instead. I use Collab so thankfully I can undo the damage done.

EDIT: 2020.2.3f1 has this problem for me, I guess I'll stay on 2020.2.2f1:
When updateing to Unity 2020.2.3f1 UIToolkit throws compile errors

 

You can try "reimporting all" after upgrading, it worked perfectly for me.

 

Before making a major change like upgrading your Unity version, you should be making a backup of your project. It is insanity not to. Unity often makes project wide changes which cannot be reversed when opened for the first time in a new version.

 

Or you can use version control and not worry about destroying anything ever again.