Index: src/core/raster/qgsrasterlayer.cpp
===================================================================
--- src/core/raster/qgsrasterlayer.cpp	(revision 15451)
+++ src/core/raster/qgsrasterlayer.cpp	(working copy)
@@ -2732,7 +2732,6 @@
 
 void QgsRasterLayer::setMinimumMaximumUsingDataset()
 {
-  double myMinMax[2];
   if ( rasterType() == QgsRasterLayer::GrayOrUndefined || drawingStyle() == QgsRasterLayer::SingleBandGray || drawingStyle() == QgsRasterLayer::MultiBandSingleBandGray )
   {
     QgsRasterBandStats myRasterBandStats = bandStatistics( bandNumber( mGrayBandName ) );
@@ -3182,27 +3181,33 @@
 
   if ( pkeyNode.isNull() )
   {
-    mProviderKey = "";
+    mProviderKey = "gdal";
   }
   else
   {
     QDomElement pkeyElt = pkeyNode.toElement();
     mProviderKey = pkeyElt.text();
+    if ( mProviderKey.isEmpty() )
+    {
+      mProviderKey = "gdal";
+    }
   }
 
   // Open the raster source based on provider and datasource
 
-  if ( !mProviderKey.isEmpty() )
-  {
-    // Go down the raster-data-provider paradigm
+  // Go down the raster-data-provider paradigm
 
-    // Collect provider-specific information
+  // Collect provider-specific information
 
-    QDomNode rpNode = layer_node.namedItem( "rasterproperties" );
+  QDomNode rpNode = layer_node.namedItem( "rasterproperties" );
 
-    // Collect sublayer names and styles
-    QStringList layers;
-    QStringList styles;
+  // Collect sublayer names and styles
+  QStringList layers;
+  QStringList styles;
+  QString format;
+
+  if ( mProviderKey == "wms" )
+  {
     QDomElement layerElement = rpNode.firstChildElement( "wmsSublayer" );
     while ( !layerElement.isNull() )
     {
@@ -3218,28 +3223,28 @@
     }
 
     // Collect format
-    QString format = rpNode.namedItem( "wmsFormat" ).toElement().text();
-
-    // Collect CRS
-    setDataProvider( mProviderKey, layers, styles, format, crs().authid() );
+    format = rpNode.namedItem( "wmsFormat" ).toElement().text();
   }
-  else
-  {
-    // Go down the monolithic-gdal-provider paradigm
 
-    if ( !readFile( source() ) )   // Data source name set in
-      // QgsMapLayer::readXML()
-    {
-      QgsLogger::warning( QString( __FILE__ ) + ":" + QString( __LINE__ ) +
-                          " unable to read from raster file " + source() );
-      return false;
-    }
+  // Collect CRS
+  setDataProvider( mProviderKey, layers, styles, format, crs().authid() );
 
+  QString theError;
+  bool res = readSymbology( layer_node, theError );
+
+  // old wms settings we need to correct
+  if ( res &&
+       mProviderKey == "wms" &&
+       mDrawingStyle == MultiBandColor &&
+       mRedBandName == TRSTRING_NOT_SET &&
+       mGreenBandName == TRSTRING_NOT_SET &&
+       mBlueBandName == TRSTRING_NOT_SET )
+  {
+    mDrawingStyle = SingleBandColorDataStyle;
+    mGrayBandName = bandName( 1 );
   }
 
-  QString theError;
-  return readSymbology( layer_node, theError );
-
+  return res;
 } // QgsRasterLayer::readXml( QDomNode & layer_node )
 
 /*
@@ -3254,13 +3259,13 @@
   QDomElement rasterPropertiesElement = document.createElement( "rasterproperties" );
   layer_node.appendChild( rasterPropertiesElement );
 
-  if ( !mProviderKey.isEmpty() )
-  {
-    QStringList sl = subLayers();
-    QStringList sls = mDataProvider->subLayerStyles();
+  QStringList sl = subLayers();
+  QStringList sls = mDataProvider->subLayerStyles();
 
-    QStringList::const_iterator layerStyle = sls.begin();
+  QStringList::const_iterator layerStyle = sls.begin();
 
+  if ( mProviderKey == "wms" )
+  {
     // <rasterproperties><wmsSublayer>
     for ( QStringList::const_iterator layerName  = sl.begin();
           layerName != sl.end();
@@ -3297,7 +3302,6 @@
       document.createTextNode( mDataProvider->imageEncoding() );
     formatElement.appendChild( formatText );
     rasterPropertiesElement.appendChild( formatElement );
-
   }
 
   // <mDrawingStyle>
Index: src/core/qgsproject.cpp
===================================================================
--- src/core/qgsproject.cpp	(revision 15451)
+++ src/core/qgsproject.cpp	(working copy)
@@ -715,7 +715,7 @@
     }
 
     // have the layer restore state that is stored in Dom node
-    if ( mapLayer->readXML( node ) )
+    if ( mapLayer->readXML( node ) && mapLayer->isValid() )
     {
       mapLayer = QgsMapLayerRegistry::instance()->addMapLayer( mapLayer );
       QgsVectorLayer* vLayer = qobject_cast<QgsVectorLayer*>( mapLayer );
@@ -746,7 +746,7 @@
     vIt->first->createJoinCaches();
     vIt->first->updateFieldMap();
     //for old symbology, it is necessary to read the symbology again after having the complete field map
-    if( !vIt->first->isUsingRendererV2() )
+    if ( !vIt->first->isUsingRendererV2() )
     {
       vIt->first->readSymbology( vIt->second, errorMessage );
     }
Index: src/providers/gdal/qgsgdalprovider.cpp
===================================================================
--- src/providers/gdal/qgsgdalprovider.cpp	(revision 15451)
+++ src/providers/gdal/qgsgdalprovider.cpp	(working copy)
@@ -131,8 +131,7 @@
   CPLErrorReset();
   if ( mGdalBaseDataset == NULL )
   {
-    QMessageBox::warning( 0, QObject::tr( "Warning" ),
-                          QObject::tr( "Cannot open GDAL dataset %1: %2" ).arg( uri ).arg( QString::fromUtf8( CPLGetLastErrorMsg() ) ) );
+    QgsDebugMsg( QString( "Cannot open GDAL dataset %1: %2" ).arg( uri ).arg( QString::fromUtf8( CPLGetLastErrorMsg() ) ) );
     return;
   }
 
@@ -301,44 +300,44 @@
   //ifdefs below to remove compiler warning about unused vars
 #ifdef QGISDEBUG
 #if 0
-    int success;
-    double GDALminimum = GDALGetRasterMinimum( myGdalBand, &success );
+  int success;
+  double GDALminimum = GDALGetRasterMinimum( myGdalBand, &success );
 
-    if ( ! success )
-    {
-      QgsDebugMsg( "myGdalBand->GetMinimum() failed" );
-    }
+  if ( ! success )
+  {
+    QgsDebugMsg( "myGdalBand->GetMinimum() failed" );
+  }
 
-    double GDALmaximum = GDALGetRasterMaximum( myGdalBand, &success );
+  double GDALmaximum = GDALGetRasterMaximum( myGdalBand, &success );
 
-    if ( ! success )
-    {
-      QgsDebugMsg( "myGdalBand->GetMaximum() failed" );
-    }
+  if ( ! success )
+  {
+    QgsDebugMsg( "myGdalBand->GetMaximum() failed" );
+  }
 
-    double GDALnodata = GDALGetRasterNoDataValue( myGdalBand, &success );
+  double GDALnodata = GDALGetRasterNoDataValue( myGdalBand, &success );
 
-    if ( ! success )
-    {
-      QgsDebugMsg( "myGdalBand->GetNoDataValue() failed" );
-    }
+  if ( ! success )
+  {
+    QgsDebugMsg( "myGdalBand->GetNoDataValue() failed" );
+  }
 
-    QgsLogger::debug( "GDALminium: ", GDALminimum, __FILE__, __FUNCTION__, __LINE__ );
-    QgsLogger::debug( "GDALmaximum: ", GDALmaximum, __FILE__, __FUNCTION__, __LINE__ );
-    QgsLogger::debug( "GDALnodata: ", GDALnodata, __FILE__, __FUNCTION__, __LINE__ );
+  QgsLogger::debug( "GDALminium: ", GDALminimum, __FILE__, __FUNCTION__, __LINE__ );
+  QgsLogger::debug( "GDALmaximum: ", GDALmaximum, __FILE__, __FUNCTION__, __LINE__ );
+  QgsLogger::debug( "GDALnodata: ", GDALnodata, __FILE__, __FUNCTION__, __LINE__ );
 
-    double GDALrange[2];          // calculated min/max, as opposed to the
-    // dataset provided
+  double GDALrange[2];          // calculated min/max, as opposed to the
+  // dataset provided
 
-    GDALComputeRasterMinMax( myGdalBand, 1, GDALrange );
-    QgsLogger::debug( "approximate computed GDALminium:", GDALrange[0], __FILE__, __FUNCTION__, __LINE__, 1 );
-    QgsLogger::debug( "approximate computed GDALmaximum:", GDALrange[1], __FILE__, __FUNCTION__, __LINE__, 1 );
+  GDALComputeRasterMinMax( myGdalBand, 1, GDALrange );
+  QgsLogger::debug( "approximate computed GDALminium:", GDALrange[0], __FILE__, __FUNCTION__, __LINE__, 1 );
+  QgsLogger::debug( "approximate computed GDALmaximum:", GDALrange[1], __FILE__, __FUNCTION__, __LINE__, 1 );
 
-    GDALComputeRasterMinMax( myGdalBand, 0, GDALrange );
-    QgsLogger::debug( "exactly computed GDALminium:", GDALrange[0] );
-    QgsLogger::debug( "exactly computed GDALmaximum:", GDALrange[1] );
+  GDALComputeRasterMinMax( myGdalBand, 0, GDALrange );
+  QgsLogger::debug( "exactly computed GDALminium:", GDALrange[0] );
+  QgsLogger::debug( "exactly computed GDALmaximum:", GDALrange[1] );
 
-    QgsDebugMsg( "starting manual stat computation" );
+  QgsDebugMsg( "starting manual stat computation" );
 #endif
 #endif
 
@@ -1184,7 +1183,10 @@
 
 int QgsGdalProvider::bandCount() const
 {
-  return GDALGetRasterCount( mGdalDataset );
+  if ( mGdalDataset )
+    return GDALGetRasterCount( mGdalDataset );
+  else
+    return 1;
 }
 
 int QgsGdalProvider::colorInterpretation( int theBandNo ) const