Timer too close


This error typically occurs when the host sends a message to the MCU, scheduling an event at a time that is in the past.


  • High system load of the host
  • High disk activity of the host
  • Swapping due to low free memory
  • Disk errors / dying SD card
  • Unstable voltage
  • Other hardware hogging the USB bus or other system resources
  • Running in a Virtual Machine
  • USB, UART or CANBUS wiring faults leading to extremely delayed messages
  • Electro-Magnetic Interference (EMI) affecting proper signal transmission or leading to high resend rates
  • Wrong Clock Reference used during building the board’s firmware (make menuconfig), confusing the timing between host and board

Potential solutions

  • Check for other resource-intensive processes running in parallel
  • Remove additional hardware, especially web cams and displays
  • Generally try to simplify your setup as much as possible
  • Check SD card for errors / replace SD card
  • Check for Under-voltage detected! errors / make sure to use a good and adequate power supply
  • Do not run data lines (USB, UART, CANBUS) close to and in parallel to high current lines like heaters or steppers. Use high quality cables (shielded / ferrite core). Keep such cables as short as possible
  • Ensure sufficient cooling of the host’s SBC to avoid CPU throttling due to overheating
  • Also see Advanced Trouble-Shooting / Graphing Klipper
  • Verify that the correct Clock Reference during building the board’s firmware is used. Mind that certain boards have various revisions / flavors that might require different clock settings