diff --git a/chrome/content/zotero/xpcom/schema.js b/chrome/content/zotero/xpcom/schema.js
index b68d3770b..01ad46a4c 100644
--- a/chrome/content/zotero/xpcom/schema.js
+++ b/chrome/content/zotero/xpcom/schema.js
@@ -2291,6 +2291,7 @@ Zotero.Schema = new function(){
 				let userSegment = yield Zotero.DB.valueQueryAsync("SELECT IFNULL((SELECT value FROM settings WHERE setting='account' AND key='userID'), 'local/' || (SELECT value FROM settings WHERE setting='account' AND key='localUserKey'))");
 				
 				let predicateID = yield Zotero.DB.valueQueryAsync("SELECT predicateID FROM relationPredicates WHERE predicate='dc:relation'");
+				if (!predicateID) continue;
 				let rows = yield Zotero.DB.queryAsync("SELECT ROWID AS id, * FROM itemRelations WHERE predicateID=?", predicateID);
 				for (let i = 0; i < rows.length; i++) {
 					let row = rows[i];