diff --git a/src/mtconnect/buffer/checkpoint.hpp b/src/mtconnect/buffer/checkpoint.hpp
index 7e2e6c5e..3b20558a 100644
--- a/src/mtconnect/buffer/checkpoint.hpp
+++ b/src/mtconnect/buffer/checkpoint.hpp
@@ -174,9 +174,17 @@ namespace mtconnect::buffer {
     /// @param[in] diMap the map of data ids to data item pointers
     void updateDataItems(std::unordered_map<std::string, WeakDataItemPtr> &diMap)
     {
-      for (auto &o : m_observations)
+      auto iter = m_observations.begin();
+      while( iter != m_observations.end() )
       {
-        o.second->updateDataItem(diMap);
+        auto item = *iter;
+        if( item.second->isOrphan() ) {
+          iter = m_observations.erase(iter);
+        }
+        else {
+          item.second->updateDataItem(diMap);
+          iter++;
+        }
       }
     }
 
diff --git a/src/mtconnect/buffer/circular_buffer.hpp b/src/mtconnect/buffer/circular_buffer.hpp
index 2bb859a6..4d30aab4 100644
--- a/src/mtconnect/buffer/circular_buffer.hpp
+++ b/src/mtconnect/buffer/circular_buffer.hpp
@@ -27,6 +27,9 @@
 #include "mtconnect/config.hpp"
 #include "mtconnect/observation/observation.hpp"
 #include "mtconnect/utilities.hpp"
+#include "mtconnect/logging.hpp"
+#include "mtconnect/entity/requirement.hpp"
+
 
 namespace mtconnect::buffer {
   using SequenceNumber_t = uint64_t;
@@ -84,9 +87,13 @@ namespace mtconnect::buffer {
     {
       for (auto &o : m_slidingBuffer)
       {
-        o->updateDataItem(diMap);
+        if( o->isOrphan() ) {
+          continue;
+        }
+        o->updateDataItem(diMap);        
       }
 
+      // checkpoints will remove orphans from its observations
       m_first.updateDataItems(diMap);
       m_latest.updateDataItems(diMap);