Starting up in verbose mode can help diagnose system issues

The next time that you boot your Mac, try holding down the Command and V keys simultaneously. This will boot Mac OS X in verbose mode, which shows all kernel and startup console message. As noted in Apple Knowledge Base article #106388, this mode can be "used for troubleshooting," but how exactly? Here are two tips for combing the on-screen output:

• Look for messages that appear on the screen along with the words "error," "failed," or "terminated." Often a specific component -- especially a kernel extension or other item that loads during the boot process -- will be mentioned. You can then use one of our sundry tutorials to troubleshoot further. "Re-installing components that are damaged or erased during the Mac OS X update process," and "Startup fails (particularly after a system or security update); solving," might be of particular use.
• Seek out messages that linger for a long period of time on the screen, especially if they are accompanied by the words "Waiting" or "Looking for...". Many times these messages will also contain the word "cache" or "caches." If this occurs, try clearing caches (with Cocktail, OnyX, MacPilot, or Tiger Cache Cleaner). In some cases, you'll see "Waiting for application service..." or "Waiting for network..." or some other "Waiting" message. In these cases it might be useful to temporarily unplug any network connections (Ethernet, etc.) and disconnect USB/FireWire devices.

Feedback? Late-breakers@macfixit.com.

Resources