diff --git a/pcbnew/files.cpp b/pcbnew/files.cpp
index 1eda4f603d..ee5122bf10 100644
--- a/pcbnew/files.cpp
+++ b/pcbnew/files.cpp
@@ -241,7 +241,14 @@ the changes?" ) ) )
         fileName.SetExt( pi->GetFileExtension() );
 
     if( !aAppend )
+    {
+        if( !wxGetApp().LockFile( fileName.GetFullPath() ) )
+        {
+            DisplayError( this, _( "This file is already open." ) );
+            return false;
+        }
         Clear_Pcb( false );     // pass false since we prompted above for a modified board
+    }
 
     CheckForAutoSaveFile( fileName, fileName.GetExt() );
 
diff --git a/pcbnew/pcbnew.cpp b/pcbnew/pcbnew.cpp
index 32fc1e2883..ff20d3c600 100644
--- a/pcbnew/pcbnew.cpp
+++ b/pcbnew/pcbnew.cpp
@@ -117,16 +117,6 @@ bool EDA_APP::OnInit()
 
     InitEDA_Appl( wxT( "Pcbnew" ), APP_PCBNEW_T );
 
-    if( m_Checker && m_Checker->IsAnotherRunning() )
-    {
-        if( !IsOK( NULL, _( "Pcbnew is already running, Continue?" ) ) )
-            return false;
-    }
-
-    // read current setup and reopen last directory if no filename to open in command line
-    bool reopenLastUsedDirectory = argc == 1;
-    GetSettings( reopenLastUsedDirectory );
-
     if( argc > 1 )
     {
         fn = argv[1];
@@ -140,10 +130,26 @@ Changing extension to .%s." ), GetChars( fn.GetFullPath() ),
             wxMessageBox( msg );
         }
 
-        if( fn.IsOk() && fn.DirExists() )
-            wxSetWorkingDirectory( fn.GetPath() );
+        if( !wxGetApp().LockFile( fn.GetFullPath() ) )
+        {
+            DisplayError( NULL, _( "This file is already open." ) );
+            return false;
+        }
     }
 
+    if( m_Checker && m_Checker->IsAnotherRunning() )
+    {
+        if( !IsOK( NULL, _( "Pcbnew is already running, Continue?" ) ) )
+            return false;
+    }
+
+    // read current setup and reopen last directory if no filename to open in command line
+    bool reopenLastUsedDirectory = argc == 1;
+    GetSettings( reopenLastUsedDirectory );
+
+    if( fn.IsOk() && fn.DirExists() )
+        wxSetWorkingDirectory( fn.GetPath() );
+
     g_DrawBgColor = BLACK;
 
     /* Must be called before creating the main frame in order to