diff --git a/chrome/content/zotero/xpcom/data/item.js b/chrome/content/zotero/xpcom/data/item.js
index ea1b02f023..9480ad86cb 100644
--- a/chrome/content/zotero/xpcom/data/item.js
+++ b/chrome/content/zotero/xpcom/data/item.js
@@ -1527,7 +1527,7 @@ Zotero.Item.prototype._saveData = Zotero.Promise.coroutine(function* (env) {
 	}
 	
 	// Tags
-	if (this._changed.tags) {
+	if (this._changed.tags && this._previousData.tags) {
 		let oldTags = this._previousData.tags;
 		let newTags = this._tags;