diff --git a/src/java/davmail/ui/tray/FrameGatewayTray.java b/src/java/davmail/ui/tray/FrameGatewayTray.java
index 883d7bb4..af6c4984 100644
--- a/src/java/davmail/ui/tray/FrameGatewayTray.java
+++ b/src/java/davmail/ui/tray/FrameGatewayTray.java
@@ -69,7 +69,8 @@ public class FrameGatewayTray implements DavGatewayTrayInterface {
         isActive = true;
         SwingUtilities.invokeLater(new Runnable() {
             public void run() {
-                if (mainFrame.getIconImage().equals(image)) {
+                Image currentImage = mainFrame.getIconImage();
+                if (currentImage != null && currentImage.equals(image)) {
                     mainFrame.setIconImage(image2);
                 } else {
                     mainFrame.setIconImage(image);