diff --git a/scour/scour.py b/scour/scour.py
index 2fc4921..53bb36e 100644
--- a/scour/scour.py
+++ b/scour/scour.py
@@ -1750,7 +1750,7 @@ def removeDefaultAttributeValue(node, attribute):
             return 1
    else:
       nodeValue = SVGLength(node.getAttribute(attribute.name))
-      if (attribute.value is None) or (nodeValue.value == attribute.value):
+      if (attribute.value is None) or ((nodeValue.value == attribute.value) and not (nodeValue.units == Unit.INVALID)):
          if (attribute.units is None) or (nodeValue.units == attribute.units) or (isinstance(attribute.units, list) and nodeValue.units in attribute.units):
             if (attribute.conditions is None) or attribute.conditions(node):
                node.removeAttribute(attribute.name)