diff --git a/src/common/application-update/discovered-update-version/discovered-update-version.injectable.ts b/src/common/application-update/discovered-update-version/discovered-update-version.injectable.ts
index ade09c8960..ad08af6331 100644
--- a/src/common/application-update/discovered-update-version/discovered-update-version.injectable.ts
+++ b/src/common/application-update/discovered-update-version/discovered-update-version.injectable.ts
@@ -13,9 +13,13 @@ const discoveredUpdateVersionInjectable = getInjectable({
   instantiate: (di) => {
     const createSyncBox = di.inject(createSyncBoxInjectable);
 
-    return createSyncBox<{ version: string; updateChannel: UpdateChannel } | null>(
-      "discovered-update-version",
-    );
+    return createSyncBox<
+      | { version: string; updateChannel: UpdateChannel }
+      | null
+      >(
+        "discovered-update-version",
+        null,
+      );
   },
 
   injectionToken: syncBoxInjectionToken,
diff --git a/src/common/application-update/progress-of-update-download/progress-of-update-download.injectable.ts b/src/common/application-update/progress-of-update-download/progress-of-update-download.injectable.ts
index c615a08a0d..7c21031f49 100644
--- a/src/common/application-update/progress-of-update-download/progress-of-update-download.injectable.ts
+++ b/src/common/application-update/progress-of-update-download/progress-of-update-download.injectable.ts
@@ -12,7 +12,7 @@ const progressOfUpdateDownloadInjectable = getInjectable({
   instantiate: (di) => {
     const createSyncBox = di.inject(createSyncBoxInjectable);
 
-    return createSyncBox<number>("progress-of-update-download");
+    return createSyncBox("progress-of-update-download", 0);
   },
 
   injectionToken: syncBoxInjectionToken,
diff --git a/src/common/application-update/update-is-being-downloaded/update-is-being-downloaded.injectable.ts b/src/common/application-update/update-is-being-downloaded/update-is-being-downloaded.injectable.ts
index 1cc2c18f64..e80a77bdd3 100644
--- a/src/common/application-update/update-is-being-downloaded/update-is-being-downloaded.injectable.ts
+++ b/src/common/application-update/update-is-being-downloaded/update-is-being-downloaded.injectable.ts
@@ -12,7 +12,7 @@ const updateIsBeingDownloadedInjectable = getInjectable({
   instantiate: (di) => {
     const createSyncBox = di.inject(createSyncBoxInjectable);
 
-    return createSyncBox<boolean>("update-is-being-downloaded");
+    return createSyncBox("update-is-being-downloaded", false);
   },
 
   injectionToken: syncBoxInjectionToken,
diff --git a/src/common/application-update/updates-are-being-discovered/updates-are-being-discovered.injectable.ts b/src/common/application-update/updates-are-being-discovered/updates-are-being-discovered.injectable.ts
index 8e18d105b6..54bc58e44a 100644
--- a/src/common/application-update/updates-are-being-discovered/updates-are-being-discovered.injectable.ts
+++ b/src/common/application-update/updates-are-being-discovered/updates-are-being-discovered.injectable.ts
@@ -12,7 +12,7 @@ const updatesAreBeingDiscoveredInjectable = getInjectable({
   instantiate: (di) => {
     const createSyncBox = di.inject(createSyncBoxInjectable);
 
-    return createSyncBox<boolean>("updates-are-being-discovered");
+    return createSyncBox("updates-are-being-discovered", false);
   },
 
   injectionToken: syncBoxInjectionToken,
diff --git a/src/common/sync-box/create-sync-box.injectable.ts b/src/common/sync-box/create-sync-box.injectable.ts
index bd92858969..5ac9c8dd04 100644
--- a/src/common/sync-box/create-sync-box.injectable.ts
+++ b/src/common/sync-box/create-sync-box.injectable.ts
@@ -17,9 +17,11 @@ const createSyncBoxInjectable = getInjectable({
     const sendToChannel = di.inject(sendToChannelInjectionToken);
     const getSyncBoxState = (id: string) => di.inject(syncBoxStateInjectable, id);
 
-    return <TData>(id: string): SyncBox<TData> => {
+    return <TData>(id: string, initialValue: TData): SyncBox<TData> => {
       const state = getSyncBoxState(id);
 
+      state.set(initialValue);
+
       return {
         id,
 
diff --git a/src/common/sync-box/sync-box.test.ts b/src/common/sync-box/sync-box.test.ts
index 458f4b6f3c..5141db40a5 100644
--- a/src/common/sync-box/sync-box.test.ts
+++ b/src/common/sync-box/sync-box.test.ts
@@ -126,12 +126,12 @@ describe("sync-box", () => {
       }, true);
     });
 
-    it("does not know initial value in main", () => {
-      expect(valueInMain).toBeUndefined();
+    it("knows initial value in main", () => {
+      expect(valueInMain).toBe("some-initial-value");
     });
 
-    it("does not know initial value in renderer", () => {
-      expect(valueInRenderer).toBeUndefined();
+    it("knows initial value in renderer", () => {
+      expect(valueInRenderer).toBe("some-initial-value");
     });
 
     describe("when value is set from main", () => {
@@ -174,6 +174,6 @@ const someInjectable = getInjectable({
   instantiate: (di) => {
     const createSyncBox = di.inject(createSyncBoxInjectable);
 
-    return createSyncBox<string>("some-state");
+    return createSyncBox("some-sync-box", "some-initial-value");
   },
 });