diff --git a/src/tasks.js b/src/tasks.js
index 68d789569..2858dc1cd 100644
--- a/src/tasks.js
+++ b/src/tasks.js
@@ -165,7 +165,7 @@ function startTask(taskId, options, callback) {
     assert.strictEqual(typeof callback, 'function');
 
     const logFile = options.logFile || `${paths.TASKS_LOG_DIR}/${taskId}.log`;
-    let fd = safe.fs.openSync(logFile, 'w'); // will autoclose
+    let fd = safe.fs.openSync(logFile, 'a'); // will autoclose. append is for apptask logs
     if (!fd) {
         debug(`startTask: unable to get log filedescriptor ${safe.error.message}`);
         return callback(new TaskError(TaskError.INTERNAL_ERROR, safe.error));