Accidentally pressing "Apply" to update all prefabs, is there an undo?

Questions & Answers
1

Yeah so, um, I’ve got about 100 instances of the same prefab, with a public variable on a script component. I’ve changed the public variable to be different for every single one. But then I press “apply”, and it’s changed every single one to the same. EVERY SINGLE ONE!

How can I undo?

2

You can’t undo that. Anyway, it’s a bit weird that this happened, since modified values on an instance of a prefab are marked as modified (the field in the inspector is in bold) and don’t get updated when the prefab changes. If it wasn’t that way, prefabs will be kind of useless.