diff --git a/chrome/content/zotero/collectionViewItemTree.jsx b/chrome/content/zotero/collectionViewItemTree.jsx
index c9f5906875..9f6057d082 100644
--- a/chrome/content/zotero/collectionViewItemTree.jsx
+++ b/chrome/content/zotero/collectionViewItemTree.jsx
@@ -1272,7 +1272,7 @@ class CollectionViewItemTree extends ItemTree {
 	_getRowData(index) {
 		var treeRow = this.getRow(index);
 		if (!treeRow) {
-			throw new Error(`Attempting to get row data for a non-existant tree row ${index}`);
+			throw new Error(`Attempting to get row data for a non-existent tree row ${index}`);
 		}
 		let itemID = treeRow.id;
 
diff --git a/chrome/content/zotero/itemTree.jsx b/chrome/content/zotero/itemTree.jsx
index a2c2bd248d..1884f1f1a5 100644
--- a/chrome/content/zotero/itemTree.jsx
+++ b/chrome/content/zotero/itemTree.jsx
@@ -2361,7 +2361,7 @@ var ItemTree = class ItemTree extends LibraryTree {
 	_getRowData(index) {
 		var treeRow = this.getRow(index);
 		if (!treeRow) {
-			throw new Error(`Attempting to get row data for a non-existant tree row ${index}`);
+			throw new Error(`Attempting to get row data for a non-existent tree row ${index}`);
 		}
 		var itemID = treeRow.id;