diff --git a/src/MainWindow.c b/src/MainWindow.c
index 28c1f07c7f..3a6551a71f 100644
--- a/src/MainWindow.c
+++ b/src/MainWindow.c
@@ -910,7 +910,7 @@ fileMenubarCB( Widget mw, XtPointer cd, XtPointer cb )
           fileMenubarCB( mw, (XtPointer)FMB_SAVE, cb );
           }
         }
-      newfile = fileBox(toplevel,OPEN, "*.dat");
+      newfile = fileBox(toplevel,OPEN, "*.xac");
       if (newfile) {
         datafile = newfile;
 
@@ -975,7 +975,7 @@ fileMenubarCB( Widget mw, XtPointer cd, XtPointer cb )
       char * newfile;
       DEBUG("FMB_SAVEAS\n");
 
-      newfile = fileBox(toplevel,OPEN, "*.dat");
+      newfile = fileBox(toplevel,OPEN, "*.xac");
       if ( newfile ) {
          datafile = newfile;
          fileMenubarCB( mw, (XtPointer)FMB_SAVE, cb );
diff --git a/src/main.c b/src/main.c
index c34ff6bf5c..c8ffa89ce0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -152,7 +152,7 @@ main( int argc, char *argv[] )
   if( argc > 1 )
     datafile = argv[1];
   else
-    datafile = fileBox( toplevel, OPEN, "*.dat" );
+    datafile = fileBox( toplevel, OPEN, "*.xac" );
   
   if( datafile != NULL )
     topgroup = readData(datafile);     /* load the accounts data from datafile*/