Index: /trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java	(revision 7343)
+++ /trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java	(revision 7344)
@@ -260,5 +260,14 @@
             return false;
         }
-        // JOSM certificate not found, install it to Windows-ROOT keystore, used by IE, Chrome and Safari, but not by Firefox
+        // JOSM certificate not found, warn user
+        StringBuilder message = new StringBuilder("<html>");
+        message.append(tr("Remote Control is configured to provide HTTPS support.<br>"+
+                "This requires to add a custom certificate generated by JOSM to the Windows Root CA store.<br><br>"+
+                "You are now going to be prompted by Windows to confirm this operation.<br>"+
+                "To enable proper HTTPS support, <b>please click Yes</b> in next dialog.<br><br>"+
+                "If unsure, you can also click No then disable HTTPS support in Remote Control preferences."));
+        message.append("</html>");
+        JOptionPane.showMessageDialog(Main.parent, message.toString(), tr("HTTPS support in Remote Control"), JOptionPane.INFORMATION_MESSAGE);
+        // install it to Windows-ROOT keystore, used by IE, Chrome and Safari, but not by Firefox
         Main.info(tr("Adding JOSM localhost certificate to {0} keystore", WINDOWS_ROOT));
         ks.setEntry(entryAlias, trustedCert, null);
