diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87e107cf9d8..ca324abe17f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 - Fixed a bug where element index result counts weren’t getting updated when the element list was refreshed but pagination was preserved. ([#15367](https://github.com/craftcms/cms/issues/15367))
 - Fixed a PHP error that occurred when making a field layout component conditional on a Time or CKEditor field. ([craftcms/ckeditor#267](https://github.com/craftcms/ckeditor/issues/267))
+- Fixed an error that occurred when editing a user via a slideout, if the current user didn’t have permission to edit the primary site. ([#15408](https://github.com/craftcms/cms/issues/15408))
 
 ## 4.10.6 - 2024-07-16
 
diff --git a/src/controllers/ElementsController.php b/src/controllers/ElementsController.php
index 2900c607124..9268f615456 100644
--- a/src/controllers/ElementsController.php
+++ b/src/controllers/ElementsController.php
@@ -1863,25 +1863,9 @@ private function _element(
         $elementId = $elementId ?? $this->_elementId;
         $elementUid = $elementUid ?? $this->_elementUid;
 
-        $sitesService = Craft::$app->getSites();
         $elementsService = Craft::$app->getElements();
         $user = static::currentUser();
 
-        if ($this->_siteId) {
-            $site = $sitesService->getSiteById($this->_siteId, true);
-            if (!$site) {
-                throw new BadRequestHttpException("Invalid side ID: $this->_siteId");
-            }
-            if (Craft::$app->getIsMultiSite() && !$user->can("editSite:$site->uid")) {
-                throw new ForbiddenHttpException('User not authorized to edit content for this site.');
-            }
-        } else {
-            $site = Cp::requestedSite();
-            if (!$site) {
-                throw new ForbiddenHttpException('User not authorized to edit content in any sites.');
-            }
-        }
-
         if ($this->_elementType) {
             $elementType = $this->_elementType;
         } elseif ($elementId || $elementUid) {
@@ -1901,12 +1885,31 @@ private function _element(
         /** @phpstan-var class-string<ElementInterface>|ElementInterface $elementType */
         $this->_validateElementType($elementType);
 
-        if ($strictSite) {
-            $siteId = $site->id;
-            $preferSites = null;
+        if ($elementType::isLocalized()) {
+            if ($this->_siteId) {
+                $site = Craft::$app->getSites()->getSiteById($this->_siteId, true);
+                if (!$site) {
+                    throw new BadRequestHttpException("Invalid side ID: $this->_siteId");
+                }
+                if (Craft::$app->getIsMultiSite() && !$user->can("editSite:$site->uid")) {
+                    throw new ForbiddenHttpException('User not authorized to edit content for this site.');
+                }
+            } else {
+                $site = Cp::requestedSite();
+                if (!$site) {
+                    throw new ForbiddenHttpException('User not authorized to edit content in any sites.');
+                }
+            }
+
+            if ($strictSite) {
+                $siteId = $site->id;
+                $preferSites = null;
+            } else {
+                $siteId = Craft::$app->getSites()->getEditableSiteIds();
+                $preferSites = [$site->id];
+            }
         } else {
-            $siteId = $sitesService->getEditableSiteIds();
-            $preferSites = [$site->id];
+            $siteId = $preferSites = null;
         }
 
         // Loading an existing element?
@@ -1942,7 +1945,7 @@ private function _element(
             throw new ForbiddenHttpException('User not authorized to edit this element.');
         }
 
-        if (!$strictSite && $element->siteId !== $site->id) {
+        if (!$strictSite && isset($site) && $element->siteId !== $site->id) {
             return $this->redirect($element->getCpEditUrl());
         }
 
@@ -1955,7 +1958,7 @@ private function _elementById(
         bool $checkForProvisionalDraft,
         string $elementType,
         User $user,
-        int|array $siteId,
+        int|array|null $siteId,
         ?array $preferSites,
     ): ?ElementInterface {
         /** @var string|ElementInterface $elementType */