--- a/browser/components/migration/MSMigrationUtils.jsm
+++ b/browser/components/migration/MSMigrationUtils.jsm
@@ -705,18 +705,22 @@ function getTypedURLs(registryKeyPath) {
           }
         }
       }
       typedURLs.set(url, timeTyped);
     }
   } catch (ex) {
     Cu.reportError("Error reading typed URL history: " + ex);
   } finally {
-    typedURLKey.close();
-    typedURLTimeKey.close();
+    if (typedURLKey) {
+      typedURLKey.close();
+    }
+    if (typedURLTimeKey) {
+      typedURLTimeKey.close();
+    }
     cTypes.finalize();
   }
   return typedURLs;
 }
 
 
 // Migrator for form passwords on Windows 8 and higher.
 function WindowsVaultFormPasswords () {