diff --git a/src/main/java/com/threerings/getdown/data/Application.java b/src/main/java/com/threerings/getdown/data/Application.java
index 422f060..84b28c9 100644
--- a/src/main/java/com/threerings/getdown/data/Application.java
+++ b/src/main/java/com/threerings/getdown/data/Application.java
@@ -1063,9 +1063,11 @@ public class Application
      *
      * @param alreadyValid if non-null a 1 element array that will have the number of "already
      * validated" resources filled in.
+     * @param unpacked a set to populate with unpacked resources.
      */
-    public List<Resource> verifyResources (ProgressObserver obs, int[] alreadyValid)
-        throws InterruptedException
+    public List<Resource> verifyResources (
+        ProgressObserver obs, int[] alreadyValid, Set<Resource> unpacked)
+            throws InterruptedException
     {
         List<Resource> rsrcs = getAllResources();
         List<Resource> failures = new ArrayList<Resource>();
@@ -1095,11 +1097,16 @@ public class Application
             try {
                 if (_digest.validateResource(rsrc, mpobs)) {
                     // unpack this resource if appropriate
-                    if (noUnpack || !rsrc.shouldUnpack() || rsrc.unpack()) {
+                    if (noUnpack || !rsrc.shouldUnpack()) {
                         // finally note that this resource is kosher
                         rsrc.markAsValid();
                         continue;
                     }
+                    if (rsrc.unpack()) {
+                        unpacked.add(rsrc);
+                        rsrc.markAsValid();
+                        continue;
+                    }
                     log.info("Failure unpacking resource", "rsrc", rsrc);
                 }
 
@@ -1116,6 +1123,40 @@ public class Application
         return (failures.size() == 0) ? null : failures;
     }
 
+    /**
+     * Unpacks the resources that require it (we know that they're valid).
+     *
+     * @param unpacked a set of resources to skip because they're already unpacked.
+     */
+    public void unpackResources (ProgressObserver obs, Set<Resource> unpacked)
+        throws InterruptedException
+    {
+        List<Resource> rsrcs = getActiveResources();
+
+        // total up the file size of the resources to unpack
+        long totalSize = 0L;
+        for (Iterator<Resource> it = rsrcs.iterator(); it.hasNext(); ) {
+            Resource rsrc = it.next();
+            if (rsrc.shouldUnpack() && !unpacked.contains(rsrc)) {
+                totalSize += rsrc.getLocal().length();
+            } else {
+                it.remove();
+            }
+        }
+
+        MetaProgressObserver mpobs = new MetaProgressObserver(obs, totalSize);
+        for (Resource rsrc : rsrcs) {
+            if (Thread.interrupted()) {
+                throw new InterruptedException("m.applet_stopped");
+            }
+            mpobs.startElement(rsrc.getLocal().length());
+            if (!rsrc.unpack()) {
+                log.info("Failure unpacking resource", "rsrc", rsrc);
+            }
+            mpobs.progress(100);
+        }
+    }
+
     /**
      * Clears all validation marker files.
      */
diff --git a/src/main/java/com/threerings/getdown/launcher/Getdown.java b/src/main/java/com/threerings/getdown/launcher/Getdown.java
index e4f512f..8efe7a8 100644
--- a/src/main/java/com/threerings/getdown/launcher/Getdown.java
+++ b/src/main/java/com/threerings/getdown/launcher/Getdown.java
@@ -51,10 +51,12 @@ import java.net.URL;
 import java.net.URLConnection;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Iterator;
 import java.util.List;
 import java.util.ResourceBundle;
+import java.util.Set;
 
 import ca.beq.util.win32.registry.RegistryKey;
 import ca.beq.util.win32.registry.RegistryValue;
@@ -404,6 +406,9 @@ public abstract class Getdown extends Thread
             // time through
             int[] alreadyValid = new int[1];
 
+            // we'll keep track of all the resources we unpack
+            Set<Resource> unpacked = new HashSet<Resource>();
+
             for (int ii = 0; ii < MAX_LOOPS; ii++) {
                 // if we aren't running in a JVM that meets our version requirements, either
                 // complain or attempt to download and install the appropriate version
@@ -431,9 +436,22 @@ public abstract class Getdown extends Thread
 
                 // now verify our resources...
                 setStatus("m.validating", -1, -1L, false);
-                List<Resource> failures = _app.verifyResources(_progobs, alreadyValid);
+                List<Resource> failures = _app.verifyResources(_progobs, alreadyValid, unpacked);
                 if (failures == null) {
                     log.info("Resources verified.");
+
+                    // if we were downloaded in full from another service (say, Steam), we may
+                    // not have unpacked all of our resources yet
+                    if (Boolean.getBoolean("check_unpacked")) {
+                        File ufile = _app.getLocalPath("unpacked.dat");
+                        if (!ufile.exists()) {
+                            log.info("Performing initial unpack.");
+                            setStatus("m.validating", -1, -1L, true);
+                            _app.unpackResources(_progobs, unpacked);
+                            ufile.createNewFile();
+                        }
+                    }
+
                     // Only launch if we aren't in silent mode. Some mystery program starting out
                     // of the blue would be disconcerting.
                     if (!_silent || _launchInSilent) {