I'm struggling with some kind of a hang that is very elusive. Apple can't seem to isolate the problem after many sysdiagnose submissions. It predominantly happens in instances of Google Chrome, Finder and even Activity Monitor (and other random apps) sometimes when certain actions are taken. The only way to recover is a sudo reboot from the shell.

No drives are actually failed or failing as one might expect. This is on a Mac Pro with ECC memory and all RAM is showing as good. I have to think that there's some dtrace tooling that would facilitate tracking down the precise point of the hang. It feels as though it's some form IO failure, but there's no indication of where or how...

What options exist for tracking down such issues at a very low level?

  • Have you tried another user account to test for user-specific problems such as corrupted .plist files and misconfigured preferences? Have you re-installed macOS in an attempt to solve the problem? – IconDaemon May 1 at 18:10
  • Yes @IconDaemon, results start to kick in again after getting things back up to a full head of steam. Problem is that reproducibility is not easy as it appears semi variable. – ylluminate May 1 at 21:00
  • So the problem recurs even after a full macOS reinstallation? If yes, I suggest you try a (temporary) other user account for a few hours just to see if it is something systemic, or just localized to your user account. For the sake of completeness, (for me at least,) I would carefully remove and firmly reseat the RAM following procedures to eliminate ESD. – IconDaemon May 2 at 11:07
  • One thing I'm looking into more closely now is how to use dtrace and Xcode instrumentation to hopefully isolate this. I'm really wanting to have a discussion surrounding this if at all possible with folks who're familiar with the lower level diagnostic tools. When you hit these kinds of issues, and Apple can't track it down on the dev support side, then one needs to work a little deeper in the system. Also setting up kernel debugging in order to attach to the kernel when full on panics that freeze the system pop up (as those happen too). – ylluminate May 2 at 14:09

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