I recently noticed that my error log is being literally flooded with "0 is not a valid connection ID" generated by signpost_notificationd process. The message is being logged few times per second.

How can I check what is causing this?

  • Are you seeing high CPU usage or other issues other than logging a lot of messages to the database?
    – bmike
    May 29, 2018 at 15:06
  • It's difficult to tell. I do see kernel_task occupying 15-25% CPU basically most of the time. That's another issue I'm trying to crack :( May 29, 2018 at 22:25

4 Answers 4


MacBookPro 2017 / MacBookPro14,3

I was getting this issue on reboot along with the high kernal_task usage. I went through the console killing of the noisiest processes and sure enough, signpost was one of them. Soon as I did, my kernal_task process dropped back to normal. It has been running at > 600%.

sudo ps aux | grep -E '^root.*signpost_notificationd' | awk '{system("sudo kill -9 " $2)}'

so this seems to be a bug in 10.13.3 or 4 - if you force-quit the signpost_notificationd process in Activity Monitor it will fix the issue until the next reboot. Note that since this is a system process, it will immediately restart, but it seems to fix the logging problem (and whatever the underlying issue is).

A lot of discussion about it here: https://discussions.apple.com/thread/8291112


This is part of signpost_reporter system which sends telemetry to Apple if you opt in to sharing crash reports and other diagnostic / usage information.

On the vast majority of our Macs - this error does get logged quite often and is harmless in that we get 0.0% CPU time even after the Macs are running for 20 to 40 days without a restart.

Unless you want to change your opt in for crash data or are seeing high CPU usage, you can probably safely ignore these errors and filter them out. Yes it's an "error" but it's not one that seems to be problematic for anyone using the system - just for processing them out of the console app or log files if you want to see other messages.

  • It's difficult to tell if it's affecting CPU. I do see kernel_task occupying 15-25% CPU basically most of the time. That's another issue I'm trying to crack :( but if those two are related then I'll be the first one to opt out from telemetry! May 29, 2018 at 22:26

As a note for everyone interested or experiencing this issue - updating to 11.13.5 resolved the problem for me. You can read through a long Apple forums thread here: https://discussions.apple.com/thread/8291112?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .