diff --git a/migen/genlib/io.py b/migen/genlib/io.py
index ecd061fa9..ab0c3bedd 100644
--- a/migen/genlib/io.py
+++ b/migen/genlib/io.py
@@ -16,4 +16,4 @@ class DifferentialInput(Special):
 
 	@staticmethod
 	def lower(dr):
-		raise NotImplementedError("Attempted to use a reset synchronizer, but platform does not support them")
+		raise NotImplementedError("Attempted to use a differential input, but platform does not support them")