diff --git a/packages/service-worker/worker/src/driver.ts b/packages/service-worker/worker/src/driver.ts
index 895fed51b63..ea3f0798abb 100644
--- a/packages/service-worker/worker/src/driver.ts
+++ b/packages/service-worker/worker/src/driver.ts
@@ -542,14 +542,8 @@ export class Driver implements Debuggable, UpdateSource {
 
       // Successfully loaded from saved state. This implies a manifest exists, so
       // the update check needs to happen in the background.
-      this.idle.schedule('init post-load (update, cleanup)', async () => {
+      this.idle.schedule('init post-load (update)', async () => {
         await this.checkForUpdate();
-        try {
-          await this.cleanupCaches();
-        } catch (err) {
-          // Nothing to do - cleanup failed. Just log it.
-          this.debugger.log(err, 'cleanupCaches @ init post-load');
-        }
       });
     } catch (_) {
       // Something went wrong. Try to start over by fetching a new manifest from the
@@ -572,6 +566,16 @@ export class Driver implements Debuggable, UpdateSource {
     // with a new copy of the manifest has been produced. At this point, the `Driver`
     // can have its internals hydrated from the state.
 
+    // Schedule cleaning up obsolete caches in the background.
+    this.idle.schedule('init post-load (cleanup)', async () => {
+      try {
+        await this.cleanupCaches();
+      } catch (err) {
+        // Nothing to do - cleanup failed. Just log it.
+        this.debugger.log(err, 'cleanupCaches @ init post-load');
+      }
+    });
+
     // Initialize the `versions` map by setting each hash to a new `AppVersion` instance
     // for that manifest.
     Object.keys(manifests).forEach((hash: ManifestHash) => {
diff --git a/packages/service-worker/worker/test/happy_spec.ts b/packages/service-worker/worker/test/happy_spec.ts
index 21955a5de40..7e15572fc8e 100644
--- a/packages/service-worker/worker/test/happy_spec.ts
+++ b/packages/service-worker/worker/test/happy_spec.ts
@@ -402,7 +402,8 @@ describe('Driver', () => {
     expect(driver['latestHash']).toBeNull();
 
     // Pushing a message initializes the driver (fetches assets).
-    await scope.handleMessage({action: 'foo'}, 'someClient');
+    scope.handleMessage({action: 'foo'}, 'someClient');
+    await new Promise(resolve => setTimeout(resolve));  // Wait for async operations to complete.
     expect(driver['latestHash']).toEqual(jasmine.any(String));
     server.assertSawRequestFor('/ngsw.json');
     server.assertSawRequestFor('/foo.txt');