diff --git a/pcbnew/connectivity.cpp b/pcbnew/connectivity.cpp
index 42285b09b6..e5627817ff 100644
--- a/pcbnew/connectivity.cpp
+++ b/pcbnew/connectivity.cpp
@@ -330,7 +330,10 @@ const std::list<BOARD_CONNECTED_ITEM*> CONNECTIVITY_DATA::GetConnectedItems(
         if( cl->Contains( aItem ) )
         {
             for( const auto item : *cl )
-                rv.push_back( item->Parent() );
+            {
+                if( item->Valid() )
+                    rv.push_back( item->Parent() );
+            }
         }
     }
 
@@ -346,7 +349,7 @@ const std::list<BOARD_CONNECTED_ITEM*> CONNECTIVITY_DATA::GetNetItems( int aNetC
 
     m_connAlgo->ForEachItem( [&items, aNetCode, &aTypes] ( CN_ITEM* aItem )
     {
-        if( aItem->Net() == aNetCode )
+        if( aItem->Valid() && aItem->Net() == aNetCode )
         {
             KICAD_T itemType = aItem->Parent()->Type();
 
@@ -406,7 +409,7 @@ const
     {
         for( auto connected : citem->ConnectedItems() )
         {
-            if( connected->Valid() &&  ( connected->Parent()->Type() == PCB_TRACE_T || connected->Parent()->Type() == PCB_VIA_T ) )
+            if( connected->Valid() && ( connected->Parent()->Type() == PCB_TRACE_T || connected->Parent()->Type() == PCB_VIA_T ) )
                 tracks.insert( static_cast<TRACK*> ( connected->Parent() ) );
         }
     }
@@ -462,6 +465,9 @@ unsigned int CONNECTIVITY_DATA::GetPadCount( int aNet ) const
 
     for( auto pad : m_connAlgo->PadList() )
     {
+        if( !pad->Valid() )
+            continue;
+
         auto dpad = static_cast<D_PAD*>( pad->Parent() );
 
         if( aNet < 0 || aNet == dpad->GetNetCode() )
@@ -508,7 +514,7 @@ const std::vector<VECTOR2I> CONNECTIVITY_DATA::NearestUnconnectedTargets(
         {
             for( auto item : *cl )
             {
-                if( item->Parent()->GetNetCode() == refNet
+                if( item->Valid() && item->Parent()->GetNetCode() == refNet
                     && item->Parent()->Type() != PCB_ZONE_AREA_T )
                 {
                     for( auto anchor : item->Anchors() )
@@ -565,7 +571,7 @@ const std::vector<BOARD_CONNECTED_ITEM*> CONNECTIVITY_DATA::GetConnectedItems(
             {
                 for( int i = 0; aTypes[i] > 0; i++ )
                 {
-                    if( cnItem->Parent()->Type() == aTypes[i] )
+                    if( cnItem->Valid() && cnItem->Parent()->Type() == aTypes[i] )
                     {
                         rv.push_back( cnItem->Parent() );
                         break;
diff --git a/pcbnew/connectivity_algo.cpp b/pcbnew/connectivity_algo.cpp
index 39d7084d97..6086159577 100644
--- a/pcbnew/connectivity_algo.cpp
+++ b/pcbnew/connectivity_algo.cpp
@@ -61,7 +61,7 @@ CN_CLUSTER::~CN_CLUSTER()
 
 wxString CN_CLUSTER::OriginNetName() const
 {
-    if( !m_originPad )
+    if( !m_originPad || !m_originPad->Valid() )
         return "<none>";
     else
         return m_originPad->Parent()->GetNetname();
@@ -78,7 +78,7 @@ bool CN_CLUSTER::Contains( const BOARD_CONNECTED_ITEM* aItem )
 {
     for( auto item : m_items )
     {
-        if( item->Parent() == aItem )
+        if( item->Valid() && item->Parent() == aItem )
             return true;
     }
 
@@ -766,7 +766,7 @@ void CN_CONNECTIVITY_ALGO::propagateConnections()
             {
                 if( item->CanChangeNet() )
                 {
-                    if( item->Parent()->GetNetCode() != cluster->OriginNet() )
+                    if( item->Valid() && item->Parent()->GetNetCode() != cluster->OriginNet() )
                     {
                         MarkNetAsDirty( item->Parent()->GetNetCode() );
                         MarkNetAsDirty( cluster->OriginNet() );
@@ -850,12 +850,18 @@ void CN_CONNECTIVITY_ALGO::MarkNetAsDirty( int aNet )
 
 int CN_ITEM::AnchorCount() const
 {
+    if( !m_valid )
+        return 0;
+
     return m_parent->Type() == PCB_TRACE_T ? 2 : 1;
 }
 
 
 const VECTOR2I CN_ITEM::GetAnchor( int n ) const
 {
+    if( !m_valid )
+        return VECTOR2I();
+
     switch( m_parent->Type() )
     {
         case PCB_PAD_T:
@@ -882,6 +888,9 @@ const VECTOR2I CN_ITEM::GetAnchor( int n ) const
 
 int CN_ZONE::AnchorCount() const
 {
+    if( !Valid() )
+        return 0;
+
     const auto zone = static_cast<const ZONE_CONTAINER*>( Parent() );
     const auto& outline = zone->GetFilledPolysList().COutline( m_subpolyIndex );
 
@@ -891,6 +900,9 @@ int CN_ZONE::AnchorCount() const
 
 const VECTOR2I CN_ZONE::GetAnchor( int n ) const
 {
+    if( !Valid() )
+        return VECTOR2I();
+
     const auto zone = static_cast<const ZONE_CONTAINER*> ( Parent() );
     const auto& outline = zone->GetFilledPolysList().COutline( m_subpolyIndex );
 
@@ -900,7 +912,7 @@ const VECTOR2I CN_ZONE::GetAnchor( int n ) const
 
 int CN_ITEM::Net() const
 {
-    if( !m_parent )
+    if( !m_parent || !m_valid )
         return -1;
 
     return m_parent->GetNetCode();
@@ -909,6 +921,7 @@ int CN_ITEM::Net() const
 
 BOARD_CONNECTED_ITEM* CN_ANCHOR::Parent() const
 {
+    assert( m_item->Valid() );
     return m_item->Parent();
 }