diff --git a/pcbnew/files.cpp b/pcbnew/files.cpp
index ed4115323..46465726e 100644
--- a/pcbnew/files.cpp
+++ b/pcbnew/files.cpp
@@ -545,6 +545,32 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
             return false;
         }
 
+        // SEGMENT fill mode no longer supported.  Make sure user is OK with converting them.
+        bool showWarning = true;
+
+        for( auto zone : loadedBoard->Zones() )
+        {
+            if( zone->GetFillMode() == ZFM_SEGMENTS )
+            {
+                if( showWarning )
+                {
+                    KIDIALOG dlg( this,
+                                  _( "The legacy segment fill mode is no longer supported.\n"
+                                     "Convert zones to polygon fills?"),
+                                  _( "Legacy Zone Warning" ),
+                                  wxYES_NO | wxICON_WARNING );
+
+                    dlg.DoNotShowCheckbox( __FILE__, __LINE__ );
+
+                    if( dlg.ShowModal() == wxID_NO )
+                        return false;
+                }
+
+                showWarning = false;
+                zone->SetFillMode( ZFM_POLYGONS );
+            }
+        }
+
         // 6.0 TODO: some settings didn't make it into the board file in 5.1 so as not to
         // change the file format.  For 5.1 we must copy them across from the config-initialized
         // board.
diff --git a/pcbnew/zone_filler.cpp b/pcbnew/zone_filler.cpp
index 000b1d0c4..1f7e1b82c 100644
--- a/pcbnew/zone_filler.cpp
+++ b/pcbnew/zone_filler.cpp
@@ -52,6 +52,28 @@
 #include "zone_filler.h"
 
 
+class PROGRESS_REPORTER_HIDER
+{
+public:
+    PROGRESS_REPORTER_HIDER( WX_PROGRESS_REPORTER* aReporter )
+    {
+        m_reporter = aReporter;
+
+        if( aReporter )
+            aReporter->Hide();
+    }
+
+    ~PROGRESS_REPORTER_HIDER()
+    {
+        if( m_reporter )
+            m_reporter->Show();
+    }
+
+private:
+    WX_PROGRESS_REPORTER* m_reporter;
+};
+
+
 extern void CreateThermalReliefPadPolygon( SHAPE_POLY_SET& aCornerBuffer,
         const D_PAD& aPad, int aThermalGap, int aCopperThickness,
         int aMinThicknessValue, int aCircleToSegmentsCount,
@@ -60,6 +82,7 @@ extern void CreateThermalReliefPadPolygon( SHAPE_POLY_SET& aCornerBuffer,
 static double s_thermalRot = 450;   // angle of stubs in thermal reliefs for round pads
 static const bool s_DumpZonesWhenFilling = false;
 
+
 ZONE_FILLER::ZONE_FILLER(  BOARD* aBoard, COMMIT* aCommit ) :
     m_board( aBoard ), m_commit( aCommit ), m_progressReporter( nullptr )
 {
@@ -86,6 +109,51 @@ bool ZONE_FILLER::Fill( std::vector<ZONE_CONTAINER*> aZones, bool aCheck )
     if( !lock )
         return false;
 
+    if( m_progressReporter )
+    {
+        m_progressReporter->Report( _( "Checking zone fills..." ) );
+        m_progressReporter->SetMaxProgress( toFill.size() );
+    }
+
+    // Preflight deprecated segment zones
+    for( auto zone : aZones )
+    {
+        if( zone->GetFillMode() == ZFM_SEGMENTS )
+        {
+            if( aCheck )
+            {
+                // Segment zones, being deprecated, are out-of-date by definition
+                PROGRESS_REPORTER_HIDER raii( m_progressReporter );
+                KIDIALOG dlg( m_progressReporter->GetParent(),
+                                       _( "Zone fills are out-of-date. Refill?" ),
+                                       _( "Confirmation" ), wxOK | wxCANCEL | wxICON_WARNING );
+                dlg.SetOKCancelLabels( _( "Refill" ), _( "Continue without Refill" ) );
+                dlg.DoNotShowCheckbox( __FILE__, __LINE__ );
+
+                if( dlg.ShowModal() == wxID_CANCEL )
+                {
+                    m_progressReporter->Show();
+                    return false;
+                }
+
+                aCheck = false;
+            }
+
+            PROGRESS_REPORTER_HIDER raii( m_progressReporter );
+            KIDIALOG dlg( m_progressReporter->GetParent(),
+                                   _( "The legacy segment fill mode is no longer supported.\n"
+                                      "Convert zones to polygon fills?"),
+                                   _( "Legacy Zone Warning" ), wxOK | wxCANCEL | wxICON_WARNING );
+            dlg.SetOKCancelLabels( _( "Convert" ), _( "Continue without Refill" ) );
+            dlg.DoNotShowCheckbox( __FILE__, __LINE__ );
+
+            if( dlg.ShowModal() != wxID_OK )
+                return false;
+
+            break;
+        }
+    }
+
     for( auto zone : aZones )
     {
         // Keepout zones are not filled
@@ -107,12 +175,6 @@ bool ZONE_FILLER::Fill( std::vector<ZONE_CONTAINER*> aZones, bool aCheck )
         zone->UnFill();
     }
 
-    if( m_progressReporter )
-    {
-        m_progressReporter->Report( _( "Checking zone fills..." ) );
-        m_progressReporter->SetMaxProgress( toFill.size() );
-    }
-
     // Remove deprecaded segment zones (only found in very old boards)
     m_board->m_SegZoneDeprecated.DeleteAll();
 
@@ -129,20 +191,13 @@ bool ZONE_FILLER::Fill( std::vector<ZONE_CONTAINER*> aZones, bool aCheck )
             ZONE_CONTAINER* zone = toFill[i].m_zone;
 
             if( zone->GetFillMode() == ZFM_SEGMENTS )
-            {
-                ZONE_SEGMENT_FILL segFill;
-                fillZoneWithSegments( zone, zone->GetFilledPolysList(), segFill );
-                zone->SetFillSegments( segFill );
-            }
-            else
-            {
-                SHAPE_POLY_SET rawPolys, finalPolys;
-                fillSingleZone( zone, rawPolys, finalPolys );
+                zone->SetFillMode( ZFM_POLYGONS );
 
-                zone->SetRawPolysList( rawPolys );
-                zone->SetFilledPolysList( finalPolys );
-            }
+            SHAPE_POLY_SET rawPolys, finalPolys;
+            fillSingleZone( zone, rawPolys, finalPolys );
 
+            zone->SetRawPolysList( rawPolys );
+            zone->SetFilledPolysList( finalPolys );
             zone->SetIsFilled( true );
 
             if( m_progressReporter )
@@ -223,27 +278,16 @@ bool ZONE_FILLER::Fill( std::vector<ZONE_CONTAINER*> aZones, bool aCheck )
             outOfDate = true;
     }
 
-    if( aCheck )
+    if( aCheck && outOfDate )
     {
-        bool refill = false;
-        wxCHECK( m_progressReporter, false );
-
-        if( outOfDate )
-        {
-            m_progressReporter->Hide();
-
-            KIDIALOG dlg( m_progressReporter->GetParent(),
-                          _( "Zone fills are out-of-date. Refill?" ),
-                          _( "Confirmation" ), wxOK | wxCANCEL | wxICON_WARNING );
-            dlg.SetOKCancelLabels( _( "Refill" ), _( "Continue without Refill" ) );
-            dlg.DoNotShowCheckbox( __FILE__, __LINE__ );
-
-            refill = ( dlg.ShowModal() == wxID_OK );
-
-            m_progressReporter->Show();
-        }
-
-        if( !refill )
+        PROGRESS_REPORTER_HIDER raii( m_progressReporter );
+        KIDIALOG dlg( m_progressReporter->GetParent(),
+                      _( "Zone fills are out-of-date. Refill?" ),
+                      _( "Confirmation" ), wxOK | wxCANCEL | wxICON_WARNING );
+        dlg.SetOKCancelLabels( _( "Refill" ), _( "Continue without Refill" ) );
+        dlg.DoNotShowCheckbox( __FILE__, __LINE__ );
+
+        if( dlg.ShowModal() == wxID_CANCEL )
         {
             if( m_commit )
                 m_commit->Revert();