Troubleshooting - Easy tricks
Quick, harmless, sometimes can help solve a problem.
- Reset PRAM: on boot, hold down Apple + Option + P.
- Reset NVRAM: on boot, hold down Apple + Option + N + V.
- Boot in Verbose mode: on boot, hold down Apple + V. Watch for errors as Mac boots, and google any errors found.
- Drain power cache: with computer off, take out battery, unplug from charger, and hold down power button for 15 seconds. Can sometimes fix a Mac that won't boot.
- Delete a program's .plist settings file: Found either in ~/Library/Preferences or in /Library/Preferences. This clears all settings for a program.
- Run Console.app to check for recent errors in Mac's log files.
Troubleshooting - Advanced
- BACK UP FILES before going on to any advanced diagnostics or tricks.
- Before trying these tricks, try installing Combo Pack updates.
Hardware troubleshooting with Apple Diagnostics
- On newer models, you can start diags by pressing F2 on booting. (Diags are preloaded onto computer.)
- On older models, insert the install disk and hold down the D key while booting. Diags are model-specific so you can't use the wrong CD.
- AppleCare-covered users can download and install TechTool Deluxe for free. A good diagnostic but to convince Apple of system failure, you'll need to use the more official Apple diagnostics.
- Symptom: Your Mac won't start up. You see a white or gray screen with a blinking/flashing question mark.
- Cause: The Mac cannot find the operating system. Most likely the hard disk has failed.
- Solutions: It's worth to try the following:
- Reset the PRAM (http://support.apple.com/kb/HT1379)
- (if this is a MacBook) Reseat the hard disk (Instructions: http://manuals.info.apple.com/en/MacBook_13inch_HardDrive_DIY.pdf)
- Try putting the Mac in Target Disk Mode and connect it to another Mac, then run Disk Utility How to run disk utility
- If the owner has the original install DVD, it can be used to repair the OS (http://support.apple.com/kb/HT1710). The Helpdesk DOES NOT have a collection of install DVDs so they cannot help if the owner does not have the install DVD.
- If none of the above helps, then it is very likely that the hard disk has failed.
If you need to get files from the computer, you can:
- Try putting the Mac in Target Disk Mode and connect it to another Mac to copy your files.
- This may not work, and if it does not, it is an indication that the hard disk has failed completely.
- If the data on the computer is very valuable, the owner can decide to contact a Professional Data Recovery Service.
- See below for repair options.
- If the computer is under warranty, the owner must contact Apple directly (call 1-800-275-2273 OR visit the Apple-authorized repair center in South Burlington: Small Dog Electronics.
- If the computer is not under warranty:
- Self-repair or repair at the Helpdesk: depending on the model (any MacBook, late 2008 MacBook Pro), it may be possible to replace the hard disk at the Helpdesk. The owner needs to purchase a replacement hard disk (see Purchasing Replacement Parts#Apple)
- For a fee, Apple or Small Dog can repair the computer: contact Apple directly (call 1-800-275-2273 OR visit the Apple-authorized repair center in South Burlington: Small Dog Electronics.
Prevention and safeguards
Hard disks eventually fail, even when best care is taken. The best solution is to purchase an external hard drive and do regular backups. External hard drives often come with software that makes the backup process automatic. External hard drives can be purchased from http://www.amazon.com http://www.newegg.com - almost any on-line shopping site sells them these days. Good brands (no particular order): Western Digital, Seagate, LaCie...
For hard drive failure
- Boot into Single User Mode by holding down Apple + S on boot.
- When system has loaded, enter
fsck -fyto check disk.
Target Disk Mode
See Target Disk Mode for how to use. Boot a Mac using another Mac's hard drive so you can:
- Access the internal hard drive without depending on it to boot the system
- Run Disk Utility to repair disk permissions
- Run Disk Warrior for advanced repair techniques
Archive & Install
Reinstalls system without touching user files (in theory). A messed-up install might be fixed this way.