diff --git a/source/net/sourceforge/filebot/Main.java b/source/net/sourceforge/filebot/Main.java
index 9494b66c..41be82e2 100644
--- a/source/net/sourceforge/filebot/Main.java
+++ b/source/net/sourceforge/filebot/Main.java
@@ -117,7 +117,7 @@ public class Main {
 				MediaTypes.getDefault();
 				
 				// check for application updates (only when installed, i.e. not running via fatjar or webstart)
-				if (System.getProperty("application.deployment") != null) {
+				if (!isPortableDeployment()) {
 					checkUpdate();
 				}
 			} catch (Exception e) {
diff --git a/source/net/sourceforge/filebot/Settings.java b/source/net/sourceforge/filebot/Settings.java
index 26ab255f..a0a50106 100644
--- a/source/net/sourceforge/filebot/Settings.java
+++ b/source/net/sourceforge/filebot/Settings.java
@@ -137,6 +137,12 @@ public final class Settings {
 	}
 	
 	
+	public static boolean isPortableDeployment() {
+		String deployment = getApplicationDeployment();
+		return deployment == null || deployment.equals("webstart");
+	}
+	
+	
 	public static int getApplicationRevisionNumber() {
 		try {
 			Manifest manifest = new Manifest(Settings.class.getResourceAsStream("/META-INF/MANIFEST.MF"));