diff --git a/category-syncer.js b/category-syncer.js
index 8bb7e8f..2e1bba3 100644
--- a/category-syncer.js
+++ b/category-syncer.js
@@ -101,8 +101,8 @@ class CategorySyncer extends EventEmitter {
             // This gives us the subtree we're interested in
             let tree = this._buildTree(categories, names, articleCounts, images, true);
 
-            // Keep unpruned tree for image sync (same subtree, but not pruned)
-            const unprunedTree = tree;
+            // Deep copy tree for unpruned version (before pruning modifies it)
+            const unprunedTree = JSON.parse(JSON.stringify(tree));
 
             // Ensure directory exists
             await fs.mkdir(this.cacheDir, { recursive: true });