diff --git a/common/prefs.cc b/common/prefs.cc
index 194bbd8..6d86a50 100644
--- a/common/prefs.cc
+++ b/common/prefs.cc
@@ -186,9 +186,8 @@
 
 bool MemoryPrefs::MemoryStorage::DeleteKey(const string& key) {
   auto it = values_.find(key);
-  if (it == values_.end())
-    return false;
-  values_.erase(it);
+  if (it != values_.end())
+    values_.erase(it);
   return true;
 }
 
diff --git a/common/prefs_unittest.cc b/common/prefs_unittest.cc
index cb6fc70..3f29319 100644
--- a/common/prefs_unittest.cc
+++ b/common/prefs_unittest.cc
@@ -358,7 +358,7 @@
 
   EXPECT_TRUE(prefs_.Delete(kKey));
   EXPECT_FALSE(prefs_.Exists(kKey));
-  EXPECT_FALSE(prefs_.Delete(kKey));
+  EXPECT_TRUE(prefs_.Delete(kKey));
 }
 
 }  // namespace chromeos_update_engine