diff --git a/pcbnew/files.cpp b/pcbnew/files.cpp
index 1008d781bd..c0cbc9f5ac 100644
--- a/pcbnew/files.cpp
+++ b/pcbnew/files.cpp
@@ -747,7 +747,8 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
         // compiled.
         Raise();
 
-        SetBoard( loadedBoard );
+        // Skip (possibly expensive) connectivity build here; we build it below after load
+        SetBoard( loadedBoard, false );
 
         if( GFootprintList.GetCount() == 0 )
             GFootprintList.ReadCacheFromFile( Prj().GetProjectPath() + "fp-info-cache" );
@@ -911,7 +912,6 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
 
     // Rebuild list of nets (full ratsnest rebuild)
     GetBoard()->BuildConnectivity();
-    Compile_Ratsnest( true );
 
     // Load project settings after setting up board; some of them depend on the nets list
     LoadProjectSettings();
diff --git a/pcbnew/pcb_edit_frame.cpp b/pcbnew/pcb_edit_frame.cpp
index 6545b5a1ad..1d5e0010ba 100644
--- a/pcbnew/pcb_edit_frame.cpp
+++ b/pcbnew/pcb_edit_frame.cpp
@@ -387,7 +387,7 @@ PCB_EDIT_FRAME::~PCB_EDIT_FRAME()
 }
 
 
-void PCB_EDIT_FRAME::SetBoard( BOARD* aBoard )
+void PCB_EDIT_FRAME::SetBoard( BOARD* aBoard, bool aBuildConnectivity )
 {
     if( m_pcb )
         m_pcb->ClearProject();
@@ -395,7 +395,9 @@ void PCB_EDIT_FRAME::SetBoard( BOARD* aBoard )
     PCB_BASE_EDIT_FRAME::SetBoard( aBoard );
 
     aBoard->SetProject( &Prj() );
-    aBoard->GetConnectivity()->Build( aBoard );
+
+    if( aBuildConnectivity )
+        aBoard->GetConnectivity()->Build( aBoard );
 
     // reload the drawing-sheet
     SetPageSettings( aBoard->GetPageSettings() );
diff --git a/pcbnew/pcb_edit_frame.h b/pcbnew/pcb_edit_frame.h
index a0b88a0585..c74dd52b81 100644
--- a/pcbnew/pcb_edit_frame.h
+++ b/pcbnew/pcb_edit_frame.h
@@ -398,7 +398,12 @@ public:
     bool Clear_Pcb( bool aQuery, bool aFinal = false );
 
     ///< @copydoc PCB_BASE_FRAME::SetBoard()
-    void SetBoard( BOARD* aBoard ) override;
+    void SetBoard( BOARD* aBoard ) override
+    {
+        SetBoard( aBoard, true );
+    }
+
+    void SetBoard( BOARD* aBoard, bool aBuildConnectivity );
 
     ///< @copydoc PCB_BASE_FRAME::GetModel()
     BOARD_ITEM_CONTAINER* GetModel() const override;