diff --git a/chrome/content/zotero/xpcom/data/tags.js b/chrome/content/zotero/xpcom/data/tags.js
index 59db23a3d..55250db05 100644
--- a/chrome/content/zotero/xpcom/data/tags.js
+++ b/chrome/content/zotero/xpcom/data/tags.js
@@ -235,6 +235,9 @@ Zotero.Tags = new function() {
 		}
 		
 		var oldTagID = this.getID(oldName);
+		if (!oldTagID) {
+			throw new Error(`Tag '${oldName}' not found`);
+		}
 		
 		// We need to know if the old tag has a color assigned so that
 		// we can assign it to the new name
@@ -255,10 +258,12 @@ Zotero.Tags = new function() {
 						+ 'WHERE tagID=? AND itemID IN (' + placeholders + ')';
 					yield Zotero.DB.queryAsync(sql, [newTagID, oldTagID].concat(chunk));
 					
-					sql = 'UPDATE items SET clientDateModified=? '
+					sql = 'UPDATE items SET clientDateModified=?, synced=0 '
 						+ 'WHERE itemID IN (' + placeholders + ')'
 					yield Zotero.DB.queryAsync(sql, [Zotero.DB.transactionDateTime].concat(chunk));
 					
+					chunk.forEach(id => Zotero.Items.get(id).updateSynced(false, true));
+					
 					yield Zotero.Items.reload(oldItemIDs, ['tags'], true);
 				})
 			);
diff --git a/test/content/support.js b/test/content/support.js
index 9f6f5dd40..05fddf8c8 100644
--- a/test/content/support.js
+++ b/test/content/support.js
@@ -414,6 +414,9 @@ function createUnsavedDataObject(objectType, params = {}) {
 		if (params.collections !== undefined) {
 			obj.setCollections(params.collections);
 		}
+		if (params.tags !== undefined) {
+			obj.setTags(params.tags);
+		}
 		break;
 	
 	case 'collection':
diff --git a/test/tests/tagsTest.js b/test/tests/tagsTest.js
index 46d7c340e..1bffdf670 100644
--- a/test/tests/tagsTest.js
+++ b/test/tests/tagsTest.js
@@ -25,6 +25,19 @@ describe("Zotero.Tags", function () {
 		})
 	})
 	
+	describe("#rename()", function () {
+		it("should mark items as changed", function* () {
+			var item1 = yield createDataObject('item', { tags: [{ tag: "A" }], synced: true });
+			var item2 = yield createDataObject('item', { tags: [{ tag: "A" }, { tag: "B" }], synced: true });
+			var item3 = yield createDataObject('item', { tags: [{ tag: "B" }, { tag: "C" }], synced: true });
+			
+			yield Zotero.Tags.rename(item1.libraryID, "A", "D");
+			assert.isFalse(item1.synced);
+			assert.isFalse(item2.synced);
+			assert.isTrue(item3.synced);
+		});
+	});
+	
 	describe("#removeFromLibrary()", function () {
 		it("should reload tags of associated items", function* () {
 			var libraryID = Zotero.Libraries.userLibraryID;