Troubleshooting the Mac - Mac Tips, Tricks & Shortcuts in easy steps (2015)

Mac Tips, Tricks & Shortcuts in easy steps (2015)


Troubleshooting the Mac

All computers go wrong from time-to-time and the Mac is no exception. This section looks at solving problems such as the Mac that refuses to boot up, ejecting rogue disks that won’t eject, corrupt files, slow Macs and how to speed them up, and wireless networking problems.

Disk Utility

This is a great utility that comes built into Mac OS X. You will find it in the Utilities folder.

Functions of Disk Utility

imageVerifying and repairing drives

imageErasing (formatting) drives

imageSetting up RAID storage

imageRestoring data from other drives

imageCreating disk images, mounting these, USB drives, and many other functions

Although you can buy many third-party apps at great expense to analyze and repair your drives, the inbuilt Disk Utility app is where you should start to troubleshoot your Mac and work with disks and their images.

Repairing permissions

If your Mac starts to misbehave, one of the first things you should do is repair the permissions using Disk Utility:

imageOpen Disk Utility and select your drive from those shown in the left pane

imageClick the First Aid and then click Repair Disk Permissions

imageRestart your Mac and see if your problem is solved



If your Mac misbehaves, run Disk Utility first and repair Disk Permissions. It may solve your problem.

Mac won’t Start

Thankfully this doesn’t happen often but it can be alarming when it does.

There are several types of non-starting Mac: gray screen, crashes during startup, black screen with three beeps, and others.

What you see depends on whether the startup problem is hardware or software-based.

General steps if your Mac will not start

imageUnplug everything you can, including USB devices and any non-essential items, leaving only keyboard and mouse connected

imageIf it still fails to boot up, you may need to remove any third-party RAM if you have installed this (black screen with three beeps indicates faulty RAM)

imageTry to start up in Safe Mode (hold down Shift when the Mac starts)

imageTry resetting the Parameter RAM (PRAM) by holding down the Command + Option + P + R keys all at the same time (you will hear the chimes then the screen will go black)

imageTry to start up in Single User Mode - hold down Command + S as the Mac starts. If you do succeed and the Mac starts, you will end up with the UNIX prompt. At this point, type in /sbin/fsck -y and the utility will report the problems

imageTry restarting from the OS X Installer disk if you have one (insert the DVD into the drive and hold down the C key as you start the Mac). If you are lucky enough to boot from this you can use Disk Utility and repair your drive

imageIf the above measures fail you may be forced to reinstall OS X

Boot into Safe Mode

To start Safe Mode, restart your Mac and hold down the Shift key.

imageThis mode forces the Mac to do a directory check on the start-up disk (as you start up into Safe Mode you will see a progress bar going along the bottom of the screen)

imageOnly the absolutely essential extensions are loaded

imageAll fonts are disabled apart from those in the main System Library

imageAll font caches are moved to the Trash

imageAll start-up items are disabled, as are login items

Using the Yosemite Recovery Partition

Macs are no longer supplied with installer disks but you can reinstall OS X from the Recovery Partition:

imageStart up your Mac whilst holding down ⌘ + R

imageYou will then see a set of OS X Utilities including: Restore From Time Machine Backup, Reinstall OS X, Get Help Online, and Disk Utility

imageTo reinstall Yosemite choose that option



Don’t forget the Yosemite Recovery Partition - use this to reinstall OS X.

Cannot Eject a Disk or Drive

Sometimes a CD, DVD, or USB drive will not eject. On older Macs, the CD/DVD drive had a small hole where you could push a paperclip and the disk would be ejected but with modern Macs this is no longer an option.

Disk is in use

If you open a document on a CD, DVD, or USB drive with an app and fail to close the document before ejecting the disk you will receive the message:


To eject the disk, close the document or quit the app and then try to eject the disk. Chances are it will eject successfully.

Eject CD or DVD that fails to eject

For a variety of reasons optical disks can simply refuse to eject.

imageRestart the Mac

imageHold down the eject button as the Mac starts to boot up

The CD/DVD will probably be ejected.

Another solution is to open Disk Utility, click the CD in the left pane, then click Eject or you can open Terminal and type drutil tray eject.


Running out of Disk Space

Over time, you install apps, take videos and accumulate large numbers of files that take up the space on your hard drive. Eventually your drive becomes full, or close to full. How can you see what’s eating all your space? You could go through your drive manually, folder by folder, or you could use an app such as GrandPerspective or OmniDiskSweeper which shows you the largest files on your drive. You can then move or delete these.



Using GrandPerspective you can see three very large files in the image above. Deleting these would salvage a lot of space on this disk!



Corrupt Preference Files

Corrupt Preference files can cause major problems when running apps. When you install an app, various files are added to your system, including the Preference file which contains information about your computer and the way you have set up your app. For example, for a word processing app the Preference file contains information about page size, printing preferences, default font and other variables. The app will load the Preference file as it starts up. If the Preference file becomes corrupt over time (not uncommon) the app will misbehave or quit.

If an app starts behaving badly, one of the first things you should do is delete its Preference file. The app will then create a new Preference file and your problem may be sorted.

Deleting a Preference file

imageGo to your ~/Library/Preferences (where ~ is your Home folder)

imageScroll through the Preferences until you find a file for your app (the file will end with .plist)

imageTrash the file and restart the app

In the example below, I have located the Finder’s Preference file which I can drag to the Trash. The Finder will immediately make a new .plist file.


Repair Disks

Over time, computer media such as disks (including USB disks) can become defective, with bad sectors. When you try to read or write data to the drive you start seeing error messages. If a drive ever starts behaving strangely, it is a good idea to check the disk integrity using Disk Utility and to repair the disk if any defects are found. The computer will make a note of the bad sectors on the disk and will not write data to those sectors.

Repairing a drive

imageOpen Disk Utility

imageClick on the First Aid tab, locate your disk from those listed in the pane on the left, and then click Verify Disk

imageIf an error is found using Verify Disk then click Repair Disk

imageIf Disk Repair cannot repair the disk you will be advised to back up as many files as you can before reformatting the drive


Speed Up your Mac!

Is your Mac starting to feel sluggish and less responsive than it was when you first got it? Chances are you have items loading at startup that could be disabled, and various other settings that are slowing the whole thing down.

Suggestions for speeding up a slow Mac

•Add more RAM - beef it up to 8 or 12GB if you can

•Disable unwanted login items

•Defragment the hard drive

•Remove unused System Preferences (the ones added by third-party apps)

•Clear caches, temporary files and other junk using OnyX, MainMenu or CCleaner

•Don’t run too many apps at once

•Restart your Mac from time-to-time

•Move massive files to external drives, e.g. large video files - this will free up useful hard drive space, then defragment the drive


Force an App to Close

Sometimes apps hang (become unresponsive) and you get the endless spinning beachball, or when you try to quit an app it stubbornly refuses to quit no matter how many times you try.

You can take control and force the app to quit using the Force Quit menu option.

Warning: sometimes an app may appear unresponsive (not responding) but is actually in the middle of processing data and if you leave it a little while longer the app behaves normally. Before you quit, make absolutely sure the app is truly unresponsive. Once you quit, the chances are you will lose any unsaved work you may have!

Force Quit an app

imageGo to Apple Menu > Force Quit...

imageFrom the window that opens choose the app you wish to quit, select it by clicking on it then click Force Quit


Memory Hogs

Apps use variable amounts of RAM and CPU power to run. Some are lean and use little but others are total memory hogs and can cause your Mac to crawl to a halt making it very difficult to do anything.

The Utility Activity Monitor allows you to see how much CPU and RAM various processes are using. If necessary, you can quit a memory hog directly from Activity Monitor and regain control of your Mac. Video apps, animation software, virtualization apps such as Parallels and VMWare use a fair bit of power in order to run. When these apps are busy they can make your Mac slow to a crawl, especially if you have limited RAM or if the Mac is old.

Using Activity Monitor

imageGo to Utilities > Activity Monitor and launch the app

imageUsing the dropdown menu at the top right select All Processes, My Processes, etc. to view the running apps and see if any are using huge amounts of your Mac’s processor

imageYou can select an app and click Quit if you want to quit the app


Activity Monitor shows that Finder, kernel_task, softwareupdated and Keynote are using a fair amount of memory, along with a few other apps.

Wireless Problem Solving

Some Macs running Yosemite drop their Wi-Fi connections randomly. On occasions the Mac reconnects automatically but other times it fails.

Add a new network

imageGo to System Preferences > Network

imagePull down the Location menu and choose Edit Locations...

imageClick the + button to add a new location and give it whatever name you want

imageClick Done

imageOn the Network screen click Network Name and join the wireless network

Now renew the DHCP lease

imageFrom the Network panel click Advanced (lower right corner) then click the TCP/IP tab

imageEnsure Configure IPv4 is set to Using DHCP then click Renew DHCP Lease then click Apply

imageThe Mac should remember the network better!