diff --git a/sui/plugin.gd b/sui/plugin.gd
index 7be64c2..8230598 100644
--- a/sui/plugin.gd
+++ b/sui/plugin.gd
@@ -1,6 +1,10 @@
 @tool
 extends EditorPlugin
 
-func _enter_tree(): pass
+func _enter_tree():
+	if !FileAccess.file_exists("res://CORE/.corebasepath") and !FileAccess.file_exists("res://addons/CORE/.corebasepath"):
+		printerr("The CORE Framework is not installed in your project.\nPlease install the CORE Framework for StarOpenSource UI to work.\nSee https://core.staropensource.de/category/getting-started/")
+	
 
-func _exit_tree(): pass
+func _exit_tree():
+	print("Thank you for using StarOpenSource UI")