diff --git a/admin/install.php b/admin/install.php
index 0882f2c0..9988904a 100644
--- a/admin/install.php
+++ b/admin/install.php
@@ -64,7 +64,9 @@ function rt_wp_nginx_helper_remove_capability( $capability ) {
 
 		foreach ( $check_order as $role ) {
 			$role = get_role( $role );
-			$role->remove_cap( $capability );
+			if ($role) {
+                          $role->remove_cap( $capability );
+                        }
 		}
 	}
 
@@ -97,4 +99,4 @@ function rt_wp_nginx_helper_get_options() {
 
 		return $rt_wp_nginx_helper_get_options;
 	}
-}
\ No newline at end of file
+}