the other thing it could be is that the .godot folder cache is now not aligned.
you could try running this script which should resave your files.
# script goes through project resaving files in editor resolving invalid UID issues
# open script in editor and run with right-click
@tool
extends EditorScript
var files: Array[String]
func _run() -> void:
files = []
add_files("res://")
for file in files:
print("fix_uid: ",file)
var res = load(file)
ResourceSaver.save(res)
func add_files(dir: String):
for file in DirAccess.get_files_at(dir):
if file.get_extension() == "tscn" or file.get_extension() == "tres" or file.get_extension() == "material":
files.append(dir.path_join(file))
for dr in DirAccess.get_directories_at(dir):
add_files(dir.path_join(dr))
The second option, you could also try deleting the .godot folder and restarting the editor.
Warning
if you do decide to try this option, it could cause you to have to reimport textures if they had custom import settings.