"This action will break the prefab instance" on project load & run

Unity Engine
1

This action will break the prefab instance
This action will break the prefab instance
This action will break the prefab instance

…I get so many of these when I open one of my projects, and also when I click to run it.

But what action? Which prefab? I have no idea where this message comes from (I’m literally not doing anything other than loading a project, and clicking play)!

2

More than likely you have a script that is causing this message. Double clicking on the warning should take you to the script and line that is causing it.

3

It’s not a warning. It’s a popup with an OK or Cancel button, so there was nothing to click on.

After I finally got tired of it, I pressed OK and it went away. I see no difference in my project for now.