diff --git a/include/etl/unordered_multimap.h b/include/etl/unordered_multimap.h
index 80ff8d91..1ca8434d 100644
--- a/include/etl/unordered_multimap.h
+++ b/include/etl/unordered_multimap.h
@@ -681,10 +681,9 @@ namespace etl
 
         // Just add the pointer to the bucket;
         bucket.insert_after(bucket.before_begin(), node);
+        adjust_first_last_markers_after_insert(pbucket);
 
         result = iterator((pbuckets + number_of_buckets), pbucket, pbucket->begin());
-
-        adjust_first_last_markers(pbucket);
       }
       else
       {
@@ -711,6 +710,7 @@ namespace etl
 
         // Add the node to the end of the bucket;
         bucket.insert_after(inode_previous, node);
+        adjust_first_last_markers_after_insert(&bucket);
         ++inode_previous;
 
         result = iterator((pbuckets + number_of_buckets), pbucket, inode_previous);
@@ -768,6 +768,7 @@ namespace etl
           bucket.erase_after(iprevious);          // Unlink from the bucket.
           icurrent->key_value_pair.~value_type(); // Destroy the value.
           pnodepool->release(&*icurrent);         // Release it back to the pool.
+          adjust_first_last_markers_after_erase(&bucket);
           ++n;
           icurrent = iprevious;
           ETL_DECREMENT_DEBUG_COUNT
@@ -806,6 +807,7 @@ namespace etl
       bucket.erase_after(iprevious);          // Unlink from the bucket.
       icurrent->key_value_pair.~value_type(); // Destroy the value.
       pnodepool->release(&*icurrent);         // Release it back to the pool.
+      adjust_first_last_markers_after_erase(&bucket);
       ETL_DECREMENT_DEBUG_COUNT
 
       return inext;
@@ -841,6 +843,7 @@ namespace etl
         local_iterator inext = pbucket->erase_after(iprevious); // Unlink from the bucket.
         icurrent->key_value_pair.~value_type(); // Destroy the value.
         pnodepool->release(&*icurrent);         // Release it back to the pool.
+        adjust_first_last_markers_after_erase(pbucket);
         ETL_DECREMENT_DEBUG_COUNT
 
         icurrent = inext;
@@ -1157,16 +1160,69 @@ namespace etl
     //*********************************************************************
     /// Adjust the first and last markers according to the new entry.
     //*********************************************************************
-    void adjust_first_last_markers(bucket_t* pbucket)
+    void adjust_first_last_markers_after_insert(bucket_t* pbucket)
     {
-      if (pbucket < first)
+      if (size() == 1)
       {
         first = pbucket;
-      }
-      else if (pbucket > last)
-      {
         last = pbucket;
       }
+      else
+      {
+        if (pbucket < first)
+        {
+          first = pbucket;
+        }
+        else if (pbucket > last)
+        {
+          last = pbucket;
+        }
+      }
+    }
+
+    //*********************************************************************
+    /// Adjust the first and last markers according to the erased entry.
+    //*********************************************************************
+    void adjust_first_last_markers_after_erase(bucket_t* pbucket)
+    {
+      if (empty())
+      {
+        first = pbuckets;
+        last = pbuckets;
+      }
+      else
+      {
+        if (pbucket == first)
+        {
+          // We erased the first so, we need to search again from where we erased.
+          while (first->empty())
+          {
+            ++first;
+          }
+        }
+        else if (pbucket == last)
+        {
+          // We erased the last, so we need to search again. Start from the first, go no further than the current last.
+          bucket_t* pbucket = first;
+          bucket_t* pend = last;
+
+          last = first;
+
+          while (pbucket != pend)
+          {
+            if (!pbucket->empty())
+            {
+              last = pbucket;
+            }
+
+            ++pbucket;
+          }
+        }
+        else
+        {
+          // Nothing to do.
+        }
+      }
     }
 
     // Disable copy construction.
diff --git a/include/etl/unordered_multiset.h b/include/etl/unordered_multiset.h
index c6e57901..2f87bd0e 100644
--- a/include/etl/unordered_multiset.h
+++ b/include/etl/unordered_multiset.h
@@ -674,11 +674,10 @@ namespace etl
 
         // Just add the pointer to the bucket;
         bucket.insert_after(bucket.before_begin(), node);
+        adjust_first_last_markers_after_insert(&bucket);
 
         result.first = iterator((pbuckets + number_of_buckets), pbucket, pbucket->begin());
         result.second = true;
-
-        adjust_first_last_markers(pbucket);
       }
       else
       {
@@ -705,6 +704,7 @@ namespace etl
 
         // Add the node to the end of the bucket;
         bucket.insert_after(inode_previous, node);
+        adjust_first_last_markers_after_insert(&bucket);
         ++inode_previous;
 
         result.first = iterator((pbuckets + number_of_buckets), pbucket, inode_previous);
@@ -763,6 +763,7 @@ namespace etl
           bucket.erase_after(iprevious);  // Unlink from the bucket.
           icurrent->key.~value_type();    // Destroy the value.
           pnodepool->release(&*icurrent); // Release it back to the pool.
+          adjust_first_last_markers_after_erase(&bucket);
           ++n;
           icurrent = iprevious;
           ETL_DECREMENT_DEBUG_COUNT
@@ -801,6 +802,7 @@ namespace etl
       bucket.erase_after(iprevious);  // Unlink from the bucket.
       icurrent->key.~value_type();    // Destroy the value.
       pnodepool->release(&*icurrent); // Release it back to the pool.
+      adjust_first_last_markers_after_erase(&bucket);
       ETL_DECREMENT_DEBUG_COUNT
 
       return inext;
@@ -836,6 +838,7 @@ namespace etl
         local_iterator inext = pbucket->erase_after(iprevious); // Unlink from the bucket.
         icurrent->key.~value_type();    // Destroy the value.
         pnodepool->release(&*icurrent); // Release it back to the pool.
+        adjust_first_last_markers_after_erase(pbucket);
         ETL_DECREMENT_DEBUG_COUNT
 
         icurrent = inext;
@@ -1152,16 +1155,69 @@ namespace etl
     //*********************************************************************
     /// Adjust the first and last markers according to the new entry.
     //*********************************************************************
-    void adjust_first_last_markers(bucket_t* pbucket)
+    void adjust_first_last_markers_after_insert(bucket_t* pbucket)
     {
-      if (pbucket < first)
+      if (size() == 1)
       {
         first = pbucket;
-      }
-      else if (pbucket > last)
-      {
         last = pbucket;
       }
+      else
+      {
+        if (pbucket < first)
+        {
+          first = pbucket;
+        }
+        else if (pbucket > last)
+        {
+          last = pbucket;
+        }
+      }
+    }
+
+    //*********************************************************************
+    /// Adjust the first and last markers according to the erased entry.
+    //*********************************************************************
+    void adjust_first_last_markers_after_erase(bucket_t* pbucket)
+    {
+      if (empty())
+      {
+        first = pbuckets;
+        last = pbuckets;
+      }
+      else
+      {
+        if (pbucket == first)
+        {
+          // We erased the first so, we need to search again from where we erased.
+          while (first->empty())
+          {
+            ++first;
+          }
+        }
+        else if (pbucket == last)
+        {
+          // We erased the last, so we need to search again. Start from the first, go no further than the current last.
+          bucket_t* pbucket = first;
+          bucket_t* pend = last;
+
+          last = first;
+
+          while (pbucket != pend)
+          {
+            if (!pbucket->empty())
+            {
+              last = pbucket;
+            }
+
+            ++pbucket;
+          }
+        }
+        else
+        {
+          // Nothing to do.
+        }
+      }
     }
 
     // Disable copy construction.
diff --git a/include/etl/unordered_set.h b/include/etl/unordered_set.h
index fb208cb4..7331cdc0 100644
--- a/include/etl/unordered_set.h
+++ b/include/etl/unordered_set.h
@@ -675,11 +675,10 @@ namespace etl
 
         // Just add the pointer to the bucket;
         bucket.insert_after(bucket.before_begin(), node);
+        adjust_first_last_markers_after_insert(&bucket);
 
         result.first = iterator(pbuckets + number_of_buckets, pbucket, pbucket->begin());
         result.second = true;
-
-        adjust_first_last_markers(pbucket);
       }
       else
       {
@@ -709,6 +708,7 @@ namespace etl
 
           // Add the node to the end of the bucket;
           bucket.insert_after(inode_previous, node);
+          adjust_first_last_markers_after_insert(&bucket);
           ++inode_previous;
 
           result.first = iterator(pbuckets + number_of_buckets, pbucket, inode_previous);
@@ -774,6 +774,7 @@ namespace etl
         bucket.erase_after(iprevious);  // Unlink from the bucket.
         icurrent->key.~value_type();    // Destroy the value.
         pnodepool->release(&*icurrent); // Release it back to the pool.
+        adjust_first_last_markers_after_erase(&bucket);
         n = 1;
         ETL_DECREMENT_DEBUG_COUNT
       }
@@ -804,6 +805,7 @@ namespace etl
       bucket.erase_after(iprevious);  // Unlink from the bucket.
       icurrent->key.~value_type();    // Destroy the value.
       pnodepool->release(&*icurrent); // Release it back to the pool.
+      adjust_first_last_markers_after_erase(&bucket);
       ETL_DECREMENT_DEBUG_COUNT
 
       return inext;
@@ -839,6 +841,7 @@ namespace etl
         local_iterator inext = pbucket->erase_after(iprevious); // Unlink from the bucket.
         icurrent->key.~value_type();    // Destroy the value.
         pnodepool->release(&*icurrent); // Release it back to the pool.
+        adjust_first_last_markers_after_erase(pbucket);
         ETL_DECREMENT_DEBUG_COUNT
 
         icurrent = inext;
@@ -1129,16 +1132,69 @@ namespace etl
     //*********************************************************************
     /// Adjust the first and last markers according to the new entry.
     //*********************************************************************
-    void adjust_first_last_markers(bucket_t* pbucket)
+    void adjust_first_last_markers_after_insert(bucket_t* pbucket)
     {
-      if (pbucket < first)
+      if (size() == 1)
       {
         first = pbucket;
-      }
-      else if (pbucket > last)
-      {
         last = pbucket;
       }
+      else
+      {
+        if (pbucket < first)
+        {
+          first = pbucket;
+        }
+        else if (pbucket > last)
+        {
+          last = pbucket;
+        }
+      }
+    }
+
+    //*********************************************************************
+    /// Adjust the first and last markers according to the erased entry.
+    //*********************************************************************
+    void adjust_first_last_markers_after_erase(bucket_t* pbucket)
+    {
+      if (empty())
+      {
+        first = pbuckets;
+        last = pbuckets;
+      }
+      else
+      {
+        if (pbucket == first)
+        {
+          // We erased the first so, we need to search again from where we erased.
+          while (first->empty())
+          {
+            ++first;
+          }
+        }
+        else if (pbucket == last)
+        {
+          // We erased the last, so we need to search again. Start from the first, go no further than the current last.
+          bucket_t* pbucket = first;
+          bucket_t* pend = last;
+
+          last = first;
+
+          while (pbucket != pend)
+          {
+            if (!pbucket->empty())
+            {
+              last = pbucket;
+            }
+
+            ++pbucket;
+          }
+        }
+        else
+        {
+          // Nothing to do.
+        }
+      }
     }
 
     // Disable copy construction.
diff --git a/test/vs2017/.vs/etl/v15/.gitignore b/test/vs2017/.vs/etl/v15/.gitignore
new file mode 100644
index 00000000..83235bb7
--- /dev/null
+++ b/test/vs2017/.vs/etl/v15/.gitignore
@@ -0,0 +1 @@
+*.VC.opendb