diff --git a/CHANGELOG.md b/CHANGELOG.md
index 276e6ac29a..21e7c8f5b1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 - Fixed a bug where the delete button would be shown for users that do not have permission to delete on the Product edit page. ([#3285](https://github.com/craftcms/commerce/issues/3285))
 - Fixed a bug where deleted shipping categories were still available for selection. ([#3272](https://github.com/craftcms/commerce/issues/3272))
 - Fixed an error that could occur when rendering a PDF. ([#2633](https://github.com/craftcms/commerce/issues/2633))
+- Fixed a bug where duplicate inactive users could be created when using the `commerce/upgrade` command. ([#3286](https://github.com/craftcms/commerce/issues/3286))
 
 ## 4.3.0 - 2023-09-13
 
diff --git a/src/console/controllers/UpgradeController.php b/src/console/controllers/UpgradeController.php
index 8b6b50dff3..ff274714cc 100644
--- a/src/console/controllers/UpgradeController.php
+++ b/src/console/controllers/UpgradeController.php
@@ -1179,6 +1179,7 @@ public function _migrateCustomers(): void
             ->leftJoin(['u' => $usersTable], 'o.email = u.email')
             ->where(['u.email' => null])
             ->andWhere(['not', ['o.email' => null]])
+            ->groupBy(['[[o.email]]'])
             ->column();
         $this->stdoutlast('  Done. Found ' . count($guestEmails) . ' guest emails.', Console::FG_GREEN);