Index: trunk/src/org/openstreetmap/josm/actions/OpenFileAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/OpenFileAction.java	(revision 4392)
+++ trunk/src/org/openstreetmap/josm/actions/OpenFileAction.java	(revision 4393)
@@ -284,10 +284,5 @@
             if (importer.isBatchImporter()) {
                 if (canceled) return;
-                String msg;
-                if (files.size() == 1) {
-                    msg = tr("Opening 1 file...");
-                } else {
-                    msg = trn("Opening {0} file...", "Opening {0} files...", files.size(), files.size());
-                }
+                String msg = trn("Opening {0} file...", "Opening {0} files...", files.size(), files.size());
                 getProgressMonitor().setCustomText(msg);
                 getProgressMonitor().indeterminateSubTask(msg);
Index: trunk/src/org/openstreetmap/josm/io/OsmImporter.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/OsmImporter.java	(revision 4392)
+++ trunk/src/org/openstreetmap/josm/io/OsmImporter.java	(revision 4393)
@@ -10,4 +10,5 @@
 import java.io.InputStream;
 
+import javax.swing.JOptionPane;
 import javax.swing.SwingUtilities;
 
@@ -39,11 +40,19 @@
     }
 
-    protected void importData(InputStream in, File associatedFile) throws IllegalDataException {
-        DataSet dataSet = OsmReader.parseDataSet(in, NullProgressMonitor.INSTANCE);
+    protected void importData(InputStream in, final File associatedFile) throws IllegalDataException {
+        final DataSet dataSet = OsmReader.parseDataSet(in, NullProgressMonitor.INSTANCE);
         final OsmDataLayer layer = new OsmDataLayer(dataSet, associatedFile.getName(), associatedFile);
         // FIXME: remove UI stuff from IO subsystem
         //
         Runnable uiStuff = new Runnable() {
+            @Override
             public void run() {
+                if (dataSet.allPrimitives().isEmpty()) {
+                    JOptionPane.showMessageDialog(
+                            Main.parent,
+                            tr("No data found in file {0}.", associatedFile.getPath()),
+                            tr("Open OSM file"),
+                            JOptionPane.INFORMATION_MESSAGE);
+                }
                 Main.main.addLayer(layer);
                 layer.onPostLoadFromFile();