diff --git a/src/HordeReconfigureFlow.php b/src/HordeReconfigureFlow.php
index c04e234..9af3b59 100644
--- a/src/HordeReconfigureFlow.php
+++ b/src/HordeReconfigureFlow.php
@@ -189,6 +189,8 @@ public function run(): int
             $mode,
         );
 
+        $themesHandler->themesCatalog->reset();
+
         foreach ($hordeThemes as $theme) {
             // register
             [$vendorName, $packageName] = explode('/', $theme);
diff --git a/src/ThemesCatalog.php b/src/ThemesCatalog.php
index a04bad9..af74999 100644
--- a/src/ThemesCatalog.php
+++ b/src/ThemesCatalog.php
@@ -111,4 +111,15 @@ public function toArray(): array
     {
         return $this->catalog;
     }
+    
+    /**
+     * Clear the in-memory catalog before a full rebuild.
+     *
+     * Callers are expected to re-register all currently installed
+     * theme packages afterwards and call save().
+     */
+    public function reset(): void
+    {
+        $this->catalog = [];
+    }
 }