Tackling a 'throttling respawn' message in the console

In OSX, background tasks are started by the main system launcher process called "launchd," which will invoke processes either at bootup, at specific time intervals (as is the case with Time Machine), or on demand when needed (such as when printing). Sometimes if a process is having trouble starting in OS X the launcher may start outputting errors in the console that mention it will "throttle respawn" for the process and will try to load it again in 10 seconds. An example of this error is as follows:

2011/05/27 5:14:11 AM     com.apple.launchd[1]     (com.icyblaze.iDocumentHelper) Throttling respawn: Will start in 10 seconds

If you see this happen on your system you may see pages of the same message over and over, which might have you wondering whether all this activity is adversely affecting system performance. Luckily, most of the time these errors have a minimal impact on the system, since they usually are quick warnings for small background processes that do not have a chance to start up. Usually the system launcher starts up and reads the configuration file for a specific process, and then tries to start the process in accordance with the configuration's instructions. The process senses some required files are not accessible and quits without using much CPU at all, and the launcher then posts the error in the console.

Depending on the specific process in question, at most the lack of it running will prevent its features from working (i.e., file sharing may not work, or a syncing tool or third-party firewall may not run).

If you see this error happening, the first thing to do is figure out what process is not launching properly by interpreting the error message, but first it helps to understand some of the organization of how OS X manages the configuration files for background processes, which are stored on one of three pairs of directories on the system:

1. System Launch Agents or Launch Daemons

   /Macintosh HD/System/Library/LaunchAgents/
   /Macintosh HD/System/Library/LaunchDaemons/

   These directories are reserved for the launch configurations for system services such as file sharing, printer sharing, and authentication agents. These folders are usually not tampered with by third-party developers, but if there is a problem with file sharing or similar system service not loading then it is likely the corresponding launch configuration file is in one of these directories. Nevertheless, these files should neither be removed nor altered.

2. Global Launch Agents or Launch Daemons

   /Macintosh HD/Library/LaunchAgents/
   /Macintosh HD/Library/LaunchDaemons/

   These directories hold the launch configurations for applications and services that affect all users on the system. Antivirus utilities and other similar system add-ons may be placed in this folder so they are loaded at start-up and run for every user. If the "Throttling Respawn" message in the console shows that the launcher generating the error has a process ID of 1 (in brackets next to the text "com.apple.launchd"), and the process being respawned is a third-party process, then the launch configuration file is likely in one of these two directories.

3. User Launch Agents or Launch Daemons

   /username/Library/LaunchAgents/
   /username/Library/LaunchDaemons/

   These directories hold the launch configurations for background tasks that run only when a specific user logs into the system. If the error in the console only shows up when you are logged into a specific user account, and the process ID number in brackets next to the text "com.apple.launchd" is greater than 1, then the launch configuration file is likely in one of these two directories.

With these locations in mind, when looking at the throttling respawn message we see the date and time of the message, along with the process identifier "com.apple.launchd[1]" which shows us the message was given by the system launcher process (the [1] shows us this is the main launcher process that is the first process invoked by the Kernel during boot). The message from launchd is that it is going to try relaunching the program "iDocumentHelper" in 10 seconds, likely because it just failed to do so.

Since the console message above is showing a third-party program (iDocumentHelper) being launched by the global system launcher (process ID of 1) so the launcher file is likely located in the /Library/LaunchAgents/ or /Library/LaunchDaemons/ folder. Launcher files can be placed in other directories, but these locations are the only ones where the launcher files will be automatically run from. The launcher file will likely be called the same name as the process indicated in the console message, so in this case it will be called "com.icyblaze.iDocumentHelper.plist".

With the launch configuration file for the program identified, this case there are two approaches you can take to prevent the errors from showing in the console: Remove the launcher file and optionally remove the entire program to prevent the error message, or reinstall the program to ensure all requirements for the program are satisfied.

1. Removing the launcher file
   With the launcher file identified, move it out of its parent folder and then reboot the system to prevent the error message from showing up. Doing this will not remove the program, but will prevent the system from trying to launch it every 10 seconds. If the program comes with an uninstaller then you should use that to uninstall it, but if not then removing the launcher file will at least keep it from starting.

2. Resintall the program
   Generally these errors happen because of a faulty installation for the program, and reinstalling or updating the program can fix the problem by reinstalling the required resources for the program. You might consider running a permissions fix on the hard drive using Disk Utility before reinstalling, since permissions errors in either the /System or /Library folders at the root of the drive could result in background processes not being able to load the files they need.

If the faulty process is a system feature such as a daemon for printing or file sharing, then your best bet is to either disable or reset those features in the system preferences and then reapply the latest Combo updater for OS X to refresh the system files for these processes. The Combo updater for your version of OS X can be downloaded from the Apple Support Downloads Web site by searching for the terms "Combo" and your version of OS X (e.g., 10.6.4, 10.6.7, etc.). In addition you might consider running a general maintenance routine on your system to clear caches and other temporary items that may be affecting the function of these processes.

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