diff --git a/src/zen/sessionstore/ZenSessionManager.sys.mjs b/src/zen/sessionstore/ZenSessionManager.sys.mjs
index 350bbfc43..a559ccf2a 100644
--- a/src/zen/sessionstore/ZenSessionManager.sys.mjs
+++ b/src/zen/sessionstore/ZenSessionManager.sys.mjs
@@ -543,6 +543,10 @@ export class nsZenSessionManager {
       this.#restoreWindowData(newWindow);
     }
     newWindow.tabs = this.#filterUnusedTabs(newWindow.tabs || []);
+    if (!lazy.gWindowSyncEnabled) {
+      // Don't bring over any unpinned tabs if window sync is disabled.
+      newWindow.tabs = newWindow.tabs.filter((tab) => tab.pinned);
+    }
 
     // These are window-specific from the previous window state that
     // we don't want to restore into the new window. Otherwise, new
diff --git a/src/zen/sessionstore/ZenWindowSync.sys.mjs b/src/zen/sessionstore/ZenWindowSync.sys.mjs
index 59e27f9eb..9e6d5ddad 100644
--- a/src/zen/sessionstore/ZenWindowSync.sys.mjs
+++ b/src/zen/sessionstore/ZenWindowSync.sys.mjs
@@ -1087,7 +1087,7 @@ class nsZenWindowSync {
     }
     tab._zenContentsVisible = true;
     tab.id = this.#newTabSyncId;
-    if (isUnsyncedWindow) {
+    if (isUnsyncedWindow || !lazy.gWindowSyncEnabled) {
       return;
     }
     this.#runOnAllWindows(window, (win) => {