20 Troubleshooting Steps for OS X: by MacOSXHints.comSo your OS X Mac isn’t working quite right. What should you do? Here’s a list of 20 basic steps to try.FIRST AID
01 Restart
02 Check/fix the filesystem
03 Make sure you’re not running out of free space on the System volume
04 Repair permissions
05 Create a new user account, and see if the problem persists there
06 Clear system & user caches
07 Disable Application Enhancer, if you’re running it
08 Startup in SafeBoot mode, and see if the problem persists there
09 Reset system firmware
10 Unplug all USB, Firewire devices except Apple mouse

MORE SERIOUS TROUBLESHOOTING 11 Reapply the latest combo updater
12 Run the Apple hardware diagnostic CD
13 Check the hard drive for bad blocks
14 Take out 3rd party RAM
15 Unplug 3rd Party PCI cards
16 Reset PMU
17 Archive and reinstall the OS
18 Reinstall the system from scratch
19 Send the machine back to Apple
20 Additional Notes

Read the rest of the hint for more detail on each of these steps…

FIRST AID

01 Restart
If a restart cures the problem, and the problem doesn’t reappear, your troubleshooting work is done. Congratulate yourself on a hard task well done.
02 Check/fix the filesystem
There are many different ways to do this. You can boot off the OS X Installation CD, run Disk Utility, and select Repair Disk. If you don’t have access to the CD, you can also run the UNIX command fsck from the Terminal in Single User Mode. The specific sequence of how to do this varies depending on what version of OS X you’re running. Go to Apple Support for specific instuctions.

Disk Utility will report back whether or not there were any problems, and whether or not it could fix any problems. If it is unable to fix a problem, then you need to get a 3rd party utility, or reformat the disk before doing any other troubleshooting. NOTE: reformatting the disk will erase it, so a 3rd party utility is usually a better idea.

You can also use a 3rd party utility like DiskWarrior or Norton Disk Doctor These 3rd party utilities can fix some kinds of errors that the free Apple tools cannot. (But don’t ever install the Norton components on your hard drive - just run the tools by booting off the Norton CD.)

If there were errors that needed to be fixed, and your software reports that they were all successfully fixed, you may have solved your larger problem.

03 Make sure you’re not running out of free space on the System volume
When the system is running out of memory, it needs to write swapfiles to your hard drive. If your hard drive is already almost full, then the system will bog down into unusability. Keep tabs on how much free space you have on your boot disk by getting info on that disk in the Finder. Alternatively, you can use the excellent freeware DiskSpace application, which will give you a display of free space on your menubar.

You should have at *least* 500MB to 1GB of free space at all times. Realistically you would want more than that, especially if you plan on burning CD/DVD’s. Remember that even if you have more free space than this when you first booted, swapfiles can eat up diskspace quickly - 2GB or more of swapfiles is not unheard of. So it’s a good idea to have at least 3GB of free space immediately after booting.

To fix: trash unneeded files and applications off of your System volume to free space. And try to create fewer swapfiles by adding more RAM or running fewer applications simultaneously. Restarting will temporarily get rid of all swapfiles, but they’ll come back.

04 Repair permissions
Run this in Disk Utility in your normal login. Open Disk Utility in the Applications/Utilities folder. Select the boot drive (probably “Macintosh HD”), click on the First Aid tab and click the Repair Permissions button. See if this cures the problem.

05 Create a new user account, and see if the problem persists there
You do this by creating a new user in the Accounts tab of System Preferences, logging out of your main account, and logging into the new account. If this makes the problem go away, it means the cause is in your user account.

While it’s good that we know approximately where the problem is, unfortunately there’s a lot of stuff in the user account to pick through. And now you will have to do some serious troubleshooting. Oftentimes, this will be a preferences file in ~/Library/Preferences/. If you can pinpoint that one bad file, you’re done. If you have no idea what’s going on you can try the laborious process of keeping that new account you made, and bringing over the files one by one until you find the one that was the problem. Even easier is to ask an expert if it’s a frequently seen problem, first letting them know that it was a problem in your user account.

06 Clear system & user caches
Use a third party tool like Cocktail or Jaguar/Panther Cache Cleaner to deep clean all caches. Reboot. See if this cures the problem.

07 Disable Application Enhancer, if you’re running it
Haxies from Unsanity. They’re great, and they’re pretty well programmed, but they’re hacking the system in non-standard ways. Unsanity claims that APE will be disabled by holding down the shift key while logging in. However, if you want to be ultra-safe about it, download the APE installer from Unsanity and use the ‘uninstaller’ option to remove all traces.

08 Startup in SafeBoot mode, and see if the problem persists there
You do this by holding down the shift key during bootup. If this makes the problem disappear, then it is a problem with Extensions or StartupItems. And most likely, those would be 3rd party Extensions or StartupItems. Most of those are kept in /Library/Extensions/ and /Library/StartupItem/. Move those items to the desktop, and see if you can isolate which one was causing the trouble. There are also some 3rd party extensions that are *annoyingly* installed in /System/Library/Extension/, however you must be very very careful mucking around in there, as almost all of those Extensions are supplied by Apple, and your machine will not function without them. Use common sense, and ask the experts.

09 Reset Firmware
Resetting your firmware will reset all firmware settings back to factory defaults. Things like the boot rom, power management, etc. are found in the firmware. To do this hold down the following buttons on your keyboard at boot up: cmd+opt+O+F. Once in open firmware type these commands:

reset-nvram (hit return) reset-all (hit return once more, the system should reboot)

10 Unplug all USB, Firewire devices except Apple mouse
Reboot with everything unplugged. If this makes the problem go away, then you have a bad external device, bad cable, or bad port on your computer. Try to isolate which one it is. Be especially wary of USB hubs.

MORE SERIOUS TROUBLESHOOTING

11 Reapply the latest combo updater
Download the latest OS X updater from Apple. These updaters come in 2 flavors, an updater which will only update the next most recent version of the OS, and a combo updater, which will update all versions since the last paid update. You want the combo updater. It will be labeled as the combo updater, and it will be much larger than the normal updaters - around 80MB at this time. Find the updater on Apply the updater, even if your system version number is already up to date. See if this cures the problem.

12 Run the Apple hardware diagnostic CD
Boot off the CD by restarting while holding down the C key on the keyboard. See if you get any useful information.

13 Check the hard drive for bad blocks
One way of doing this is to try to re-initialize your drive using Drive Setup from the OS X Installation disk. Unfortunately, this will wipe out all of your data, so back up first, if that’s the route you go. If the initialization fails, your disk is worthless garbage and must be replaced.

You can use the TechTool Deluxe CD that came with the Apple Protection Plan to check for bad blocks. Norton Disk Doctor will also allow you to test for bad blocks without erasing your disk using the Check Media option. Other 3rd party disk utilities may allow this as well. Hearing odd noises coming from your drive is a tip-off that this may be your trouble.

14 Take out 3rd party RAM
See if this cures the problem.

15 Unplug 3rd Party PCI cards
If this solves the problem, replace the cards one by one until you identify the problematic card. Contact the manufacturer to see if updated drivers are available.

16 Reset PMU
The PMU’s (Power Management Unit’s) location, and how to reset it, varies by machine. Go to Apple Support to find out how to do it for your particular machine. See if this cures the problem. Typically this will fix issues when your system will not power on.

Make sure you only hold in the PMU button for a second. DO NOT hold it in for any longer and DO NOT press it more than once. If you do this it could result in corrupting the PMU itself.

17 Archive and Install OS X
This will archive user/network settings and replace your current system folder with a new one. Boot off your OS X cd and run through the install as normal. Once you get to the screen where you select which hard drive you want to put the OS on there should be an options button under the hard drive. Select it and then select the archive and reinstall button. Then proceed through the install as normal. This may or may not fix your problem, and it can save you time from copying back ups back over, resetting user preferences, and reinstalling applications.

18 Reinstall the system from scratch
This step is annoying and time consuming, which is why we’ve saved it for second to last. It requires erasing your hard drive, so you’ll have to either back up, or lose, all of your data. Apple’s instructions for doing this can be found here.

19 Send the machine back to Apple
This step is very annoying, very time-consuming, and if the machine is out of warranty, can be very very expensive. So try a couple of the other steps first. Call Apple Support to arrange a pickup or locate an an Apple Authorized Service Provider by clicking here (for the USA; this article explains what to do in other countries.

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20 Additional Notes

Uninstall Norton Products if you’ve installed them
Norton Utilities, Anti-Virus, and SystemWorks are hazardous to the health of your OS X system when installed. It’s perfectly safe to run Norton Utilities booted off a CD or OS 9 volume, but you should seriously consider unistalling them if you’ve installed them on your OS X volume. They’re trouble.

As of this time, anti-virus utilities are useless on OS X. There are no known system-wide viruses on OS X. There are indeed viruses that can contaminate documents inside Microsoft Office X, but there are preferences in those applications to protect against this.

Check your error logs
Check your system logs to see if there is anything relevant to your problem listed there. To do so simply go to the apple menu and select about this computer. A window will pop up displaying some basic information about your computer. Click on the more info button at the bottom of the window. This will bring up Apple System Profiler (ASP). The last tab furthest to the right of the ASP will be labled “Logs�? click on it and then select console. It should list error messages related to each application you are having problems with.

Start your system in verbose mode
Start up your computer in verbose mode, hold down cmd+V at start up. You will see the a bunch of text scroll down the screen as everything starts up. Look for anything that gives an error message and record it. Try doing google searches, or search forums to see if the problem has already been discussed and a known fix has been established. A lot of times you can find fixes on these forums, they are a great tool.

ESD safety is important when working inside your computer
You do not want to damage any component when removing it. Refer to the manual that came with your computer, or Apple Support on the web.

Acknowlegments
This list was refined with the contributions of many folks on the MacOSXHints Forums. You can see their contributions in this thread; special thanks to tlarkin for his dedicated work.