# Internal error in MCU 'mcu' stepcompress and lost connection with MMB

**URL:** <https://klipper.discourse.group/t/internal-error-in-mcu-mcu-stepcompress-and-lost-connection-with-mmb/20251>\
**Category:** General Discussion\
**Created:** [November 25, 2024, 12:08pm UTC](https://klipper.discourse.group/t/internal-error-in-mcu-mcu-stepcompress-and-lost-connection-with-mmb/20251 "2024-11-25T12:08:29Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\
**Post date:** [November 25, 2024, 12:18pm UTC](https://klipper.discourse.group/t/internal-error-in-mcu-mcu-stepcompress-and-lost-connection-with-mmb/20251/2 "2024-11-25T12:18:30Z")

</div>

The original error is

```auto
Timeout with MCU 'MMB' (eventtime=8629.364980)
Transition to shutdown state: Lost communication with MCU 'MMB'

```

See [Timeout with MCU / Lost communication with MCU](https://klipper.discourse.group/t/timeout-with-mcu-lost-communication-with-mcu/6639)  
The rest seem to be consequential errors that are likely unrelated to the root cause.

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