diff --git a/chrome/content/zotero/xpcom/data_access.js b/chrome/content/zotero/xpcom/data_access.js
index 6cc50f064..96482cdc6 100644
--- a/chrome/content/zotero/xpcom/data_access.js
+++ b/chrome/content/zotero/xpcom/data_access.js
@@ -585,9 +585,9 @@ Zotero.Item.prototype.setField = function(field, value, loadIn){
 		}
 		// Validate access date
 		else if (fieldID == Zotero.ItemFields.getID('accessDate')) {
-			if (!Zotero.Date.isSQLDate(value) &&
+			if (value && (!Zotero.Date.isSQLDate(value) &&
 					!Zotero.Date.isSQLDateTime(value) &&
-					value != 'CURRENT_TIMESTAMP') {
+					value != 'CURRENT_TIMESTAMP')) {
 				Zotero.debug("Discarding invalid accessDate '" + value
 					+ "' in Item.setField()");
 				return false;