diff --git a/chrome/content/zotero/xpcom/sync/syncEngine.js b/chrome/content/zotero/xpcom/sync/syncEngine.js
index 92cd4a177..fb5e62a86 100644
--- a/chrome/content/zotero/xpcom/sync/syncEngine.js
+++ b/chrome/content/zotero/xpcom/sync/syncEngine.js
@@ -1011,20 +1011,20 @@ Zotero.Sync.Data.Engine.prototype._uploadObjects = Zotero.Promise.coroutine(func
 			Zotero.logError("Error for " + objectType + " " + batch[index].key + " in "
 				+ this.library.name + ":\n\n" + e);
 			
-			// This shouldn't happen, because the upload request includes a library
-			// version and should prevent an outdated upload before the object version is
-			// checked. If it does, we need to do a full sync.
+			// This shouldn't happen, because the upload request includes a library version and should
+			// prevent an outdated upload before the object version is checked. If it does, we need to
+			// do a full sync. This error is checked in handleUploadError().
 			// TEMP - Revert after 2016-08-19
 			//if (e.code == 412) {
 			if (e.code == 404 || e.code == 412) {
-				return this.UPLOAD_RESULT_OBJECT_CONFLICT;
+				throw e;
 			}
 			
 			if (this.onError) {
 				this.onError(e);
 			}
 			if (this.stopOnError) {
-				throw new Error(e);
+				throw e;
 			}
 			batch[index].tries++;
 			// Mark 400 errors as permanently failed
@@ -1477,11 +1477,19 @@ Zotero.Sync.Data.Engine.prototype._handleUploadError = Zotero.Promise.coroutine(
 				return this.UPLOAD_RESULT_CANCEL;
 			}
 			throw new Error(`Unexpected index value ${index}`);
-			
+		
 		case 412:
 			return this.UPLOAD_RESULT_LIBRARY_CONFLICT;
 		}
 	}
+	else if (e.name == "ZoteroObjectUploadError") {
+		switch (e.code) {
+		// TEMP - Revert after 2016-08-19
+		case 404:
+		case 412:
+			return this.UPLOAD_RESULT_OBJECT_CONFLICT;
+		}
+	}
 	throw e;
 });
 
diff --git a/test/tests/syncEngineTest.js b/test/tests/syncEngineTest.js
index 982964196..b36730216 100644
--- a/test/tests/syncEngineTest.js
+++ b/test/tests/syncEngineTest.js
@@ -2136,6 +2136,44 @@ describe("Zotero.Sync.Data.Engine", function () {
 			// Library version shouldn't have changed
 			assert.equal(group.libraryVersion, 5);
 		});
+		
+		
+		it("should trigger full sync on object conflict", function* () {
+			({ engine, client, caller } = yield setup());
+			
+			var library = Zotero.Libraries.userLibrary;
+			var libraryID = library.id;
+			var lastLibraryVersion = 5;
+			library.libraryVersion = lastLibraryVersion;
+			yield library.saveTx();
+			
+			var item = createUnsavedDataObject('item');
+			item.version = lastLibraryVersion;
+			yield item.saveTx();
+			
+			setResponse({
+				method: "POST",
+				url: "users/1/items",
+				status: 200,
+				headers: {
+					"Last-Modified-Version": lastLibraryVersion
+				},
+				json: {
+					successful: {},
+					unchanged: {},
+					failed: {
+						"0": {
+							"code": 412,
+							"message": `Item doesn't exist (expected version ${lastLibraryVersion}; `
+								+ "use 0 instead)"
+						}
+					}
+				}
+			});
+			
+			var result = yield engine._startUpload();
+			assert.equal(result, engine.UPLOAD_RESULT_OBJECT_CONFLICT);
+		});
 	});