If you’ve just recovered from a system crash, you might be told to check the Console for error messages. But what do those Console messages mean, and how can you interpret the logs to troubleshoot your Mac?
What Is the Console?
Console is the application that collects log messages from your computer for user review. It collects errors, warnings and standard “here’s what I did” log messages from system and user applications. It’s a fantastic resource for troubleshooting. It should be your first stop after your computer experiences a random restart, kernel panic or application crash.
You can find the Console application with “Applications -> Utilities -> Console.app,” or by typing “Console” into the Spotlight or Launchpad search bars.
Getting Acquainted with Console
When you first open Console, you’ll be confronted by a torrent of real-time log messages. Most of these are unimportant, mundane application reports describing what the application is doing at that moment. It’s not material that’s typically important for the user to know, but if you want to find it, that’s where it lives.
You can toggle off Console’s stream of consciousness by clicking the “Now” button in the upper-right or by scrolling up.
This will “freeze” Console messages at the current moment, but new messages will continue to come in at the bottom of the queue. You just won’t be auto-scrolled to them.
To remove currently visible messages from the Console, click the “Clear” button in the menu bar. This will let you focus on just what’s happening now. The view will be reloaded soon after you click Clear, and new log messages will begin to appear.
But we don’t really care about these standard log messages. We’re interested in seeing the problems. To see only log messages about problems, click “Errors and Faults” below the menu bar.
If you look at the search bar in the upper-right of the window, you’ll notice that Errors and Faults is really just a saved search. You can create your own searches by manipulating the search bar.
If you’ve made a custom search you like and want to save it to the filter bar, click the “Save” button.
Interpreting Console Messages to Troubleshoot Your Mac
The most important types of console messages are errors and faults, which we filtered for above.
These reports tell you when something has gone wrong in the world of your computer and may or may not require addressing. Faults, the most serious console message, get red dots, while errors, which are more like warning messages, get yellow dots.
The process column will tell you the name of the application or system process that sent the error. Some will be familiar, and others will be foreign to you. The most serious faults are typically spawned by the “kernel” process.
To learn more about a specific message, click on it and check out the info pane at the bottom of the window.
Evaluating Individual Faults and Errors
The info window returns a lot of cryptic information for non-expert users. On the top we see the process that spawned the error message, along with the specific sub-process in parentheses. If you click the “Show” link next to the subsystem and category, you can reveal the Activity ID, Thread ID and PID. PID is the identification number of the process. The Thread ID can describe which part of the process caused the problem, but it’s most useful to the creators of the software. Activity ID will almost always be zero.
Below all that identifying information we see the actual log message. In this case I can see that IOReturn is complaining that it can’t unlock the IOAccelSurface2 because the surface is not locked. It’s not important if you don’t know what this means right way, but it often gives you a unique phrase to search. Googling this error leads me to believe it’s a bug with TeamViewer but not critically important.
Conclusion: When Should I Check the Console?
Console is most useful when your system has just experienced an error. Maybe an application failed to open and you received a System Report window about it. Or maybe you just rebooted following a kernel panic. Inspecting the Console will help you dig up the cause of the problem and take the necessary steps to fix it.