diff --git a/src/main/java/com/threerings/getdown/launcher/GetdownApp.java b/src/main/java/com/threerings/getdown/launcher/GetdownApp.java
index 8840531..0dbac85 100644
--- a/src/main/java/com/threerings/getdown/launcher/GetdownApp.java
+++ b/src/main/java/com/threerings/getdown/launcher/GetdownApp.java
@@ -68,7 +68,7 @@ public class GetdownApp
         }
 
         // look for a specific app identifier
-        String appId = (aidx < args.size()) ? args.get(aidx++) : null;
+        String appId = (aidx < args.size()) ? args.get(aidx++) : System.getProperty("appid");
 
         // pass along anything after that as app args
         String[] appArgs = (aidx < args.size()) ?