Apple MD094LL/A manual Intermittent Shutdown, Troubleshooting Shutdown Causes

Intermittent Shutdown

Troubleshooting Shutdown Causes

Always run the latest available Apple service utilities to check for any abnormal value reading from a thermal, a voltage, or a current sensor, or from a fan speed meter. The log files may also report the cause of a previous shut down(s).

Collect all available info from user on shut down occurrence details: periodicity, power state when issue happens, running applications, running time before shutdown.

Shutdown events can be categorized into four different areas.

1) User-related shut downs:

A computer shut-down event may be caused by user operation. The following shut down methods should not be considered as a failure, unless the power button is found to be defective.

•Selecting Shut Down by choosing the Apple () menu from the upper-left menu bar and then choosing Shut Down.

•Pressing and holding the power button for 10 seconds

•Programming a timed shutdown in the Energy Saver preferences: refer to  menu>System Preferences>Energy Saver

Suggested troubleshooting steps are:

•Reset the SMC: Refer to: kBase #HT3964: Intel-based iMac: How to reset the System

Management Controller

•Check Energy Saver preferences settings: choosing the Apple () menu>System Preferences>Energy Saver

•Test the Power On button for an intermittent short that would force computer to shutdown.

2) Activity-related system shut downs:

•System could not succeed the standard shutdown process and had to force shutdown

•An installed watchdog detected that an application did not respond within specified time (this watchdog can be enabled on Mac O X Server Energy Saver preferences)

These shut downs may be linked to system settings, devices drivers, applications, or operating system freezes.

Suggested troubleshooting steps are:

•Check the system logs and activity monitor utility for clues on the freezing process,

•Check for available software and firmware updates for installed device drivers, applications, or operating system

•Start the system from a known-good / up-to-date bootable drive for issue reproduction.

2010-09-09 iMac (27-inch, Mid 2010) Symptom Charts — Startup and Power  39