diff --git a/src/apps.js b/src/apps.js
index 534c14700..392e7cad4 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -645,7 +645,7 @@ function checkAppState(app, state) {
     assert.strictEqual(typeof app, 'object');
     assert.strictEqual(typeof state, 'string');
 
-    if (app.taskId) return new BoxError(BoxError.BAD_STATE, `Not allowed in this app state : ${app.installationState} / ${app.runState}`);
+    if (app.taskId) return new BoxError(BoxError.BAD_STATE, `Locked by task ${app.taskId} : ${app.installationState} / ${app.runState}`);
 
     if (app.installationState === exports.ISTATE_ERROR) {
         if (app.error.installationState === state) return null;