diff --git a/modules/programs/firefox.nix b/modules/programs/firefox.nix
index b19b0960..5984187c 100644
--- a/modules/programs/firefox.nix
+++ b/modules/programs/firefox.nix
@@ -78,7 +78,24 @@ let
         version = 4;
         lastUserContextId =
           elemAt (mapAttrsToList (_: container: container.id) containers) 0;
-        identities = mapAttrsToList containerToIdentity containers;
+        identities = mapAttrsToList containerToIdentity containers ++ [
+          {
+            userContextId = 4294967294; # 2^32 - 2
+            name = "userContextIdInternal.thumbnail";
+            icon = "";
+            color = "";
+            accessKey = "";
+            public = false;
+          }
+          {
+            userContextId = 4294967295; # 2^32 - 1
+            name = "userContextIdInternal.webextStorageLocal";
+            icon = "";
+            color = "";
+            accessKey = "";
+            public = false;
+          }
+        ];
       }}
     '';
 
@@ -677,6 +694,20 @@ in {
           (", namely " + concatStringsSep ", " defaults);
       })
 
+      (let
+        getContainers = profiles:
+          flatten
+          (mapAttrsToList (_: value: (attrValues value.containers)) profiles);
+
+        findInvalidContainerIds = profiles:
+          filter (container: container.id >= 4294967294)
+          (getContainers profiles);
+      in {
+        assertion = cfg.profiles == { }
+          || length (findInvalidContainerIds cfg.profiles) == 0;
+        message = "Container id must be smaller than 4294967294 (2^32 - 2)";
+      })
+
       (mkNoDuplicateAssertion cfg.profiles "profile")
     ] ++ (mapAttrsToList
       (_: profile: mkNoDuplicateAssertion profile.containers "container")
diff --git a/tests/modules/programs/firefox/container-id-out-of-range.nix b/tests/modules/programs/firefox/container-id-out-of-range.nix
new file mode 100644
index 00000000..5dbeaedd
--- /dev/null
+++ b/tests/modules/programs/firefox/container-id-out-of-range.nix
@@ -0,0 +1,27 @@
+{ config, lib, ... }:
+
+{
+  imports = [ ./setup-firefox-mock-overlay.nix ];
+
+  config = lib.mkIf config.test.enableBig {
+    test.asserts.assertions.expected =
+      [ "Container id must be smaller than 4294967294 (2^32 - 2)" ];
+
+    programs.firefox = {
+      enable = true;
+
+      profiles.my-profile = {
+        isDefault = true;
+        id = 1;
+
+        containers = {
+          "shopping" = {
+            id = 4294967294;
+            color = "blue";
+            icon = "circle";
+          };
+        };
+      };
+    };
+  };
+}
diff --git a/tests/modules/programs/firefox/default.nix b/tests/modules/programs/firefox/default.nix
index b0c4fadb..1cd462f2 100644
--- a/tests/modules/programs/firefox/default.nix
+++ b/tests/modules/programs/firefox/default.nix
@@ -4,5 +4,6 @@
   firefox-deprecated-native-messenger = ./deprecated-native-messenger.nix;
   firefox-duplicate-profile-ids = ./duplicate-profile-ids.nix;
   firefox-duplicate-container-ids = ./duplicate-container-ids.nix;
+  firefox-container-id-out-of-range = ./container-id-out-of-range.nix;
   firefox-policies = ./policies.nix;
 }