Wednesday, February 3, 2010

In Depth: 20 common Mac problems solved

Very nice article from TechRadar.

In Depth: 20 common Mac problems solved: "

The trouble with Macs is that they lull you into a false sense of security. If you spend your day using PCs, dealing with infuriating glitches becomes second nature. But Apple has made things so straightforward that you get used to stuff just working. When it doesn't, it comes as a nasty shock.

It's quite hard to identify the most common Mac problems, because most problems aren't all that common. They can range from minor annoyances that we'll all see once in a while, like applications slowing down or files behaving oddly, to the almost mythical calamities that many users will never encounter, like disk failures and kernel panics.

Sometimes it may seem obvious where to look for the solution; other times, you won't have a clue. Fortunately, the brick walls you may occasionally run up against will generally turn out, on closer inspection, to be mere ha-has in the garden of Mac.

Here are some of the daily hiccups you're most likely to suffer...

1. Persistent beachball

Quite often, the pointer turns into a spinning beach ball while your Mac has a think. Occasionally it stays that way.

First, try pressing Cmd+. to cancel whatever process is afoot. If that has no effect, switch to Finder or another app (using Option+Tab), and carry on working. If you wait, the app will finish what it's doing and give you its full attention.

Beachball

If you're convinced the app isn't going to recover, force it to quit by holding Option or by pressing Cmd+Option+Esc. Rarely, it refuses to die, or its windows may disappear while its Dock icon retains its open indicator.

Restarting your Mac will get rid of it, but could give a message saying the app failed to quit. Hold down the power button to force shutdown.

You can also use a Unix command for this: run Terminal – found in Utilities within the Applications folder – and type sudo shutdown –h. Close other apps first to avoid losing data.

2. Lost a file

The first thing to do when you think you've mislaid an important file is to ask Spotlight. Press Cmd+[Space] to open the search bar, and type as much of the filename as you remember; pause after each letter to see what comes up.

If you've overwritten your work with a new file of the same name, or emptied the Trash, you've got a problem. Time Machine users can feel smug, as Spotlight will find files that don't currently exist but have been backed up. The software is built into OS X 10.5 and later, and the only hardware you need is a USB or FireWire hard disk.

USB drive

If you haven't set it up yet, you may need a disk-recovery utility such as Data Rescue 2. This detects and restores deleted files as well as tackling more general disk problems.

It's wise to stop using the disk as soon as you realise you're missing something; the likelihood of rescuing a deleted file depends on whether new data has been saved over it.

3. Switching is slow

Modern Macs are happy for you to run lots of apps at the same time – in fact, there's no limit. Yet your Mac has a finite amount of memory (RAM), so what gives?

It's done with 'virtual memory'. When Mac OS X runs out of space in RAM for all the programs and data you're using at once, it moves some of them to a hidden temporary file on the hard disk. This works so seamlessly that you don't notice it.

But with a lot of apps on the go, it can end up happening each time you switch between them, and with major apps and large files this can take a little time.

A solution is to close some programs. Deleting files from your hard disk won't help; it's the space in RAM that's the issue. So the answer is more RAM. To check how much your Mac can take, select the model in the Memory Advisor at www.crucial.com/uk.

Crucial memory advisor

Upgrading may mean adding more memory modules or replacing the existing ones with higher-capacity chips.

4. Safari is slow

A solution to a troublesome Safari is to choose Reset Safari from its menu and reset everything. If there's a regular delay before pages load, perhaps Safari isn't looking for them efficiently.

Go to the Network pane of System Preferences, click your internet connection (Ethernet or AirPort), then Advanced, and go to the DNS tab. Under DNS Servers, you'll see nothing or the IP address of your router, greyed out.

Set dns

This leaves Mac OS X to find a default DNS (domain name server) that translates the web addresses you type into the actual IP addresses where sites are hosted. Pointing it to a specific DNS could speed things up.

Choose OpenDNS. Click + and enter 208.67.222.222, repeat and enter 208.67.220.220. See www.opendns.com/start/computer for more details.

5. Documents open in the wrong app

Although hardly a catastrophe, this can be an ongoing source of vexation. Yet it's easy to fix once you know how. For example, when you download a JPEG file, double-clicking it will normally open Preview. But if you habitually use Photoshop to work with photos, Preview may be irrelevant.

To change this, select any JPEG and press Cmd+I (Get Info). Under Open with, select your preferred app, such as Photoshop, and click Change All. Confirm this and all JPEGs will always open in Photoshop.

This works for any combination of file type and compatible application. The files themselves aren't changed; you're just altering the Mac OS's list of file associations.

More than just irksome, these symptoms mean serious business…

6. Mac won't start

A total lack of response to the power button could mean a blown fuse in the plug, so check first. If it's not completely dead, the Mac will do a 'power-on self-test' (POST) as it boots up, and beep if it finds a fault. The power LED may flash too.

One, two or three beeps points the finger at RAM modules (see here for more info). Try easing them into place, in case they've become unseated. Your manual will tell you how to get at the RAM, or go to www.apple.com/support and search for 'install memory' and your Mac's model name.

Four and five beeps indicate problems with the system ROM or processor, while the Air also has an 'SOS' code consisting of three short, three long and then three short beeps. If you hear these, seek professional Mac help.

7. Need to rescue my files

If something's amiss with your Mac, copy off as much data as you can before anything else happens. This may be possible even when you can't access Finder, using FireWire Target Disk mode.

You'll need another Mac: see this page, and compare specs in System Profiler (go to About This Mac on the Apple menu and click More Info).

Turn off the problem Mac, leaving the other running. Unplug any FireWire peripherals and connect a FireWire cable between the two (use one with a 6-pin connector, not the 4-pin video camera plug).

Start up your problem Mac, holding down T. This is the target Mac, while the other is the host. The target should appear as an icon on the host's Desktop, and you can drag files off it.

8. Mac starts, but stops

Startup might stall with a plain blue or grey screen, a flashing question mark, a broken folder icon, or – rarely – a 'sad Mac'. Sometimes, especially in the last instance, you may have a hardware problem, but let's look on the bright side.

Sad mac

Installed Snow Leopard and got a grey screen? Check out http://support.apple.com/kb/TS2990, as it could be due to an incomplete previous update.

Plugged in a USB or FireWire device? It could be incompatible or conflict with another peripheral; unplug everything and restart. Memory upgrades can sometimes get through the POST (see Tip 6) but then crash; try re-installing. The same goes for other internal upgrades.

Nothing so obvious? Try a Safe Boot, which adds extra self tests. Shut down, then start up while holding Shift. If this works, immediately try a normal restart.

Otherwise, reset the PRAM. To do this hold down Option+Cmd+P+R before the grey screen appears; check the hard disk (Tip 15); and read this page and this page.

9. Kernel panic

When the OS crashes it can only bow out with the message 'You need to restart your computer'. This is a kernel panic. It's rare and, thankfully, often fixed by restarting.

If not, try unplugging all add-ons from your Mac and restarting. Internal upgrades – including dodgy RAM – can provoke kernel panics, as can devices such as USB hubs. Another possibility is that a system file has become corrupted.

Kernel panic

Restart while holding x; if this works, go to System Preferences, click Startup Disk and ensure the correct disk is selected. Or, restart holding down Option, releasing it when icons appear; you'll be asked which disk to start up from. Or zap the PRAM (see the tip above).

If none of those work, perhaps you've moved, renamed or deleted a system file. Reversing this may sort it out – or not.

The last resort is to reinstall Mac OS X. Start up from your Mac's OS X DVD, run the installer and choose Archive and Install. You'll need to reinstall your apps, though.

10. An application is playing up

When an application suddenly no longer works properly, a common cause is corrupted preferences. Each application has its own preference files containing configuration data, and because they're read and written so often these are rather susceptible to corruption.

When an app crashes, Mac OS X may offer to reset its preferences. You can also do this manually.

Preference files, identified by the extension .plist, are stored in /Library/Preferences (on your main hard disk) and in /user/Library/Preferences, where user is your user account's home folder. Look here and you can usually see which prefs belong to which apps.

Having quit the application, make a folder on the Desktop called Suspect prefs (for example) and move all the app's preference files into this. Now relaunch the app. This forces it to rebuild its plists, which should solve the problem.

If it doesn't, just put the plists back. Some apps also have self-repair functions; for example, holding the Option key while launching may bring up a settings box. Have a look in your app's manual. Otherwise, you'll have to reinstall the application from its DVD or disc image file (.dmg).

Tame your Mac's disk drives and save yourself some hassle

11. I can't eject a disc

You want to use a CD or DVD, but there's already one in your Mac. So you hit the Eject button and… nothing happens. What now?

Daft as it sounds, try holding the button down longer. A slight delay has been added to stop you ejecting discs accidentally. You can tap the Option key to hurry it up.

Still no joy? Find the disc on the Desktop and drag it onto the Trash icon in the Dock. Or click the Eject icon besides the disc's name at the left of any Finder window.

Still not coming out? Launch Terminal, found in /Applications/Utilities, type drutil tray open and press Return. That should do the trick.

No? The final option is to restart your Mac while holding down the left mouse-button. External disk and memory drives can also fail to eject, usually because software is refusing to let go of them. Close the likely culprits: for example, iPhoto. If you have this problem often, try the free utility WhatsOpen.

12. My hard disk is full

Running out of room on your hard disk may manifest itself in an alert box warning that it's 'nearly full'; or programs such as Photoshop failing to complete operations; or your Mac generally slowing down.

On any hard disk, files are invisibly split into chunks to fit into the gaps left by previous additions and deletions. The more 'fragmented' a drive becomes, the harder it has to work. A rule of thumb is that you should leave 10% of the disk empty to minimise fragmentation.

Hard disk

To check how full the disk is, select its icon on the Desktop (or in the sidebar of any Finder window) and press Cmd+i.

Under General, you'll see how much is free. When space gets tight, delete some files. Move work onto an external drive, and remove apps you don't use.

Use Spotlight to find unwanted files. Press Cmd+F in Finder to open a search, then set the criteria. For example, choose Kind, is, Other, then type disk image: this will find all the .dmg files you downloaded to install programs and no longer need.

Or switch from Kind to Size, choose is greater than and enter, say, 50MB. Delete files within the search results by selecting them and pressing Cmd+Del: they don't disappear, but their details, in the bar at the bottom, show they now reside in the Trash.

Empty the Trash otherwise all you've 'deleted' is still on your hard disk.

13. My optical drive won't read

CD and DVD drives are susceptible to dust, which can build up on the lens that directs the laser onto the disc. In general, this isn't something you need to worry about; as attempting regular cleaning can do more harm than good.

But if the drive stops working, try a lens-cleaning disc such as the Philips SVC2520/10, £4 from www.amazon.co.uk. Follow the instructions and you could find your dead drive lives again. There's a small chance that it could make things worse – but it worked for our Mac mini.

14. Flash drive won't read

Unplugging a memory drive without ejecting it can leave it in an inaccessible state, and some computers not made by Apple have a habit of killing memory sticks.

If a flash drive is playing up, you can reformat it using Disk Utility, found in /Applications/Utilities.

Verify disk

When plugged in, the drive should appear on the left, even if it didn't show up in Finder. If not, it's time to buy a new drive. Having selected the device, you can check it in the First Aid tab and try the Repair option, but this is designed for hard disks and may not help.

More likely, you'll need to go to the Erase tab and reformat it. Choose MS-DOS (FAT), which works with both Macs and PCs, and click Erase (not Erase Free Space).

15. Something just seems funny

Your Mac starts up fine but runs slowly; or applications and files lose their icons; or certain functions stop working. Which component is to blame?

Well, while most are marvels of solid state, the hard disk basically still consists of a roulette wheel full of iron filings and a fishing rod with a magnet on the end. This is not a recipe for reliability.

The home of drive maintenance is Disk Utility, in /Applications/Utilities. Select your drive in the panel on the left; you'll notice it has two icons, one for the hard disk itself, another for the 'logical partition' containing your data (named Macintosh HD by default).

Select either, then go to the First Aid tab and click Verify Disk. This checks the data structure; any errors it finds can usually be fixed by clicking Repair Disk.

However, if this is your main hard disk, you can't repair it while the Mac OS is running off it, so you'll need to restart with your OS DVD, holding the C key to boot from it.

Having repaired your hard disk, restart while holding down the left mouse-button to eject the DVD and restart.

If the repair fails, you'll be asked if you want to erase the disk; obviously you don't, and your next stop should be an engineer. First copy any vital files onto an external drive, and avoid writing new files to the hard disk.

The other handy tool here is Repair Disk Permissions. Permissions are an obscure but important feature of the operating system – explained here – that can cause oddness if they go wrong. Just click the button to fix them.

To round off, a multi-purpose miscellany of troubleshooting tips

16. Forgotten password

The great thing about password protected user accounts is that other people can't get at your stuff. But if you forget the password, you can't get at it either.

However, if your Mac starts up with a login request and you've forgotten it, all you need is the OS X DVD that came with the computer. Insert and restart, holding the C key to make sure your Mac boots from the DVD.

Reset password

You'll find a Utilities menu that includes the command Reset Password. Do it, then restart, holding down the left mouse-button.

If you used FileVault (in the Security pane of System Preferences) to encrypt your home folder, the procedure is different. To override your FileVault password you need your master password.

Don't know this either? The only way to get data back is to crack the 1024-bit RSA encryption algorithm, which according to a recent paper, won't happen until 'at least until 2014'.

17. Screen goes weird

If the screen suddenly looks messed up, a restart is often all that's required.

With CRT monitors, it was possible to choose from a combination of resolutions and refresh rates that would result in an illegible display, but with today's LCDs the worst that can happen is an inappropriate resolution forces the screen to 'upsample', giving a slightly pixellated appearance.

Screen

If your display becomes illegible or blank, the video configuration has gone seriously adrift. This can often be fixed by zapping the PRAM: see tip 8.

18. Failed to sync

Syncing email, contacts and calendars between your Mac and iPhone or iPod touch is probably the best reason to subscribe to Apple's MobileMe service. However, now and then, you may find the information you expected to see on your device isn't there.

Like any online service, MobileMe itself can suffer glitches. Log in to www.me.com (in Safari) and check the Contacts and Calendar pages. If your data is correct there, but not on your device, it's probably just temporary, so give it a few minutes (staying online) to fix itself.

To confirm whether there's a fault with MobileMe, check System Status on your Summary page. If this isn't the cause, try resetting your sync data. Check that the data on your Mac is the version you want to keep; if you've added info on your iPhone or iPod, it's going to get overwritten.

Mobile me

Go to System Preferences. Click MobileMe, go to the Sync tab and click Advanced, then click Reset Sync Data. Choose All Sync Info from the Replace popup menu, then click the right arrow button, making the orange arrow go from the Mac to MobileMe.

Current data will be copied from your Mac to your MobileMe account, which should propagate it to your iPhone or touch. Or, 'turn it off and turn it on again'. Restart by holding the power button until Slide to power off appears, do that, then press the button again to turn it back on.

Go to Settings > Mail, Contacts, Calendars > MobileMe. Using the sliders, turn off each item that isnt syncing properly. When this is confirmed, go to the relevant app and check the data has gone. Then turn syncing on again.

19. Audio input/output broken

Sometimes you'll find your Mac isn't hearing you, or vice versa. The reason can often be found in the Sound pane of System Preferences. The tabs are: Sound Effects (controls noises made by Mac OS X and apps); Output (controls speakers and headphones); and Input (controls microphones and other sound sources).

Plugging headphones or speakers into the headphone jack diverts the signal from the internal speaker, so Headphones replaces Internal speaker in the device list. However, your Mac remembers the Output volume you last used for your headphones, and applies this.

In the Input tab, increasing the Input volume slider should increase the level on the meter as you make a noise. If no blue dots light up, your microphone isn't working. Note that on the latest iMacs, the mic is above the webcam; placing things over this will kill mic input.

20. Cleanup needed

Spilling liquids on your Mac is a nightmare scenario. With a laptop, grab it quickly – being wary of any non-MagSafe cables – and turn it upside down, allowing as much liquid as possible to run off; then shut it down and leave it in a warm (not hot) and dry place to recover.

Clean off any residue with a cotton bud slightly dampened with water. With desktop Macs it's usually the keyboard that gets it. Unplug, turn upside down, then assess the damage.

If the liquid has gone right inside and is something that won't easily evaporate away, like a fizzy drink or beer, consider running the whole thing under the tap; this shouldn't cause permanent damage as long as you dry it out fully, leaving it somewhere warmish for a day or so, before reconnecting.

This is, of course, entirely at your own risk. On a less mission-critical theme, white MacBooks can get grubby quickly. A clean cloth lightly dampened with plain water is safe to use, but what if it doesn't shift the marks?

Try erasing them with, yes, an eraser, which should only set you back a couple of quid. If this doesn't work, some users recommend Magic Eraser, the spongy stuff filled with a cleaning agent. Or, Apple's recommended cleaner, iKlear, is available from the Apple Store at £14.95 for 59ml.



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