diff --git a/index.js b/index.js
index 878236b..fcf91d0 100644
--- a/index.js
+++ b/index.js
@@ -112,6 +112,7 @@ const ContextualIdentityProxy = {
 const ContainerService = {
   _identitiesState: {},
   _windowMap: new Map(),
+  _containerWasEnabled: false,
 
   init(installation) {
     // If we are just been installed, we must store some information for the
@@ -159,6 +160,10 @@ const ContainerService = {
       }
     }
 
+    // Let's see if containers were enabled before this addon.
+    this._containerWasEnabled =
+      ss.storage.savedConfiguration.prefs["privacy.userContext.enabled"];
+
     // Enabling preferences
 
     PREFS.forEach((pref) => {
@@ -1005,16 +1010,16 @@ const ContainerService = {
 
     for (let window of windows.browserWindows) { // eslint-disable-line prefer-const
       // Let's close all the container tabs.
-      // Note 1: we don't care if containers are supported but the current FF
-      //         version.
-      // Note 2: We cannot use _closeTabs() because at this point tab.window is
-      //         null.
-      for (let tab of window.tabs) { // eslint-disable-line prefer-const
-        if (this._getUserContextIdFromTab(tab)) {
-          tab.close();
-          try {
-            SessionStore.forgetClosedTab(viewFor(window), 0);
-          } catch(e) {} // eslint-disable-line no-empty
+      // Note: We cannot use _closeTabs() because at this point tab.window is
+      // null.
+      if (!this._containerWasEnabled) {
+        for (let tab of window.tabs) { // eslint-disable-line prefer-const
+          if (this._getUserContextIdFromTab(tab)) {
+            tab.close();
+            try {
+              SessionStore.forgetClosedTab(viewFor(window), 0);
+            } catch(e) {} // eslint-disable-line no-empty
+          }
         }
       }