# "MCU 'mcu' shutdown: Timer too close" - unknown cause **URL:** \ **Category:** General Discussion\ **Created:** [July 8, 2023, 8:58pm UTC](https://klipper.discourse.group/t/mcu-mcu-shutdown-timer-too-close-unknown-cause/9367 "2023-07-08T20:58:22Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [July 9, 2023, 5:52am UTC](https://klipper.discourse.group/t/mcu-mcu-shutdown-timer-too-close-unknown-cause/9367/2 "2023-07-09T05:52:34Z")
Hello @Orbiter07 ! Please have a look here: > [@Timer too close](https://klipper.discourse.group/t/timer-too-close/6634/1): > > Timer too close Background A “Timer too close” error occurs when the MCU is asked to schedule an action at a time that is already in the past. This typically results from delayed communication between the host and the MCU - for instance, if the host was busy or the message was blocked en route. warning Important: Klipper can identify what command was too late, but cannot determine why the delay occurred. The root cause is often external - such as USB congestion from a webcam or high system … --- _[View the full topic](https://klipper.discourse.group/t/mcu-mcu-shutdown-timer-too-close-unknown-cause/9367)._