diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+# 0.1.0.1
+
+Quickfix for an oversight in the `uninsertSum` function that broke
+`splitSum`.
+
 # 0.1.0.0
 
 Initial release.  Expect the public-facing API to change as the
diff --git a/named-sop.cabal b/named-sop.cabal
--- a/named-sop.cabal
+++ b/named-sop.cabal
@@ -1,5 +1,5 @@
 name:                named-sop
-version:             0.1.0.0
+version:             0.1.0.1
 category:            Data
 
 homepage:            https://github.com/sjsch/named-sop
diff --git a/src/Data/NamedSOP/Sum.hs b/src/Data/NamedSOP/Sum.hs
--- a/src/Data/NamedSOP/Sum.hs
+++ b/src/Data/NamedSOP/Sum.hs
@@ -106,7 +106,7 @@
 uninsertSum sxk (SCons syk _) (NSumThis v) = case sCompare sxk syk of
   SLT -> Left v
   SEQ -> Left v
-  SGT -> error "unsorted list"
+  SGT -> Right (NSumThis v)
 uninsertSum sxk (SCons syk sys) (NSumThat vs) = case sCompare sxk syk of
   SLT -> Right vs
   SEQ -> Right vs