\n<\/p>\n
Every time Apple releases any system update, online communities go wild with reports of problems. These problems are always blamed on bugs by some, and discussions degenerate into vitriolic arguments. The truth is that, although bugs can and do happen, there are many common problems that recur frequently and have nothing to do with bugs. This means that it is prudent for anyone having problems following an update to try troubleshooting those problems, rather than assuming they are caused by a bug and waiting for someone else to fix them.<\/p>\n
Computers are very complex machines, and depend on a complex interaction of many hardware and software components. \u00a0Any little thing can potentially gum up the works, and when that happens, the average user has no idea where to turn. \u00a0In order to understand how to approach such a problem, it is first necessary to gain an understanding of the potential causes for problems.<\/p>\n
The first and most obvious reason that an upgrade can cause problems is presence of bugs. \u00a0This is the one everyone tends to blame most of the time, but actually, bugs are rarely the source of serious problems. \u00a0It does happen sometimes, though. \u00a0Consider, for example, the guest login bug in Mac OS X 10.6 and 10.6.1, which could cause an entire user account to disappear, taking all that user\u2019s data with it. \u00a0That was a major bug, which Apple did acknowledge and eventually figured out how to fix in 10.6.2. \u00a0In general, however, system upgrades and updates are tested pretty thoroughly, and only less significant bugs are likely to slip through testing undiscovered. \u00a0Since major bugs are rare and you would have to wait for Apple to fix them anyway, it\u2019s almost always more productive to seek other causes for update problems.<\/p>\n
Another source of problems is incompatible third-party software. \u00a0Developers have documentation available to them that tells them how to do things, and they should follow those directions closely to ensure their programs function properly. \u00a0However, sometimes developers don\u2019t follow those instructions closely enough, or they followed the instructions very closely ten years ago and the rules have changed by now. \u00a0In either case, changes to the system eventually catch up with them, and their code stops working properly. \u00a0This can cause all manner of problems, including (but not limited to) crashing,\u00a0kernel panics<\/a>,\u00a0cosmetic bugs and even data loss in extreme cases.<\/p>\n A third possibility is corruption. \u00a0Corruption occurs whenever data is unintentionally modified, causing some or all of the data in question to be replaced by what is essentially random data. \u00a0This can cause very serious problems, even failure of the computer to start up if a vital file becomes corrupt, can cause data loss in a user\u2019s documents or all manner of other issues. \u00a0Corruption can exist without notice, until the installation of a new system writes thousands of files, worsening the corruption and further damaging a slightly damaged system. \u00a0Imagine going into a factory and removing one component from the machinery at random, replacing it with some random object. \u00a0That could cause the entire factory to shut down or could be completely unnoticeable until just the right set of circumstances occurred, depending on the part that was removed.<\/p>\n Lack of resources \u2013 RAM, hard drive space, processor speed, and so on \u2013 can be a cause for performance problems, and in extreme cases can even cause crashes. \u00a0Often, major new versions of the system are more demanding than the previous version. \u00a0Mac OS X 10.7 (Lion), for example, requires a minimum of 2 GB of RAM, while Mac OS X 10.6 (Snow Leopard) only required 1 GB and Mac OS X 10.5 (Leopard) needed a minimum of 512 MB. \u00a0Newer software with higher requirements is not likely to run as well as a previous version did on the same hardware. \u00a0(I, for example, had to upgrade my computer\u2019s RAM to 8 GB after installing Lion, due to RAM-related issues that were not present in the less-demanding Snow Leopard.)<\/p>\n Causes can also include hardware failures, contrary to popular belief. \u00a0Sometimes hardware has a minor flaw that is not a problem until a new system stresses it in a new way. \u00a0Other times, certain hardware can fail as an unrelated side-effect of installing an upgrade. \u00a0For example, the act of writing thousands of files to the hard drive may push a drive on the verge of failure over the edge. \u00a0Finally, one should not discount the coincidental failure. \u00a0To many people, it seems wrong to say that a hardware failure that happens at exactly the same time as a system update is coincidence, but coincidences do happen. \u00a0In addition, the failure may not have actually been coincidental\u2026 \u00a0for example, someone who hasn\u2019t used their optical drive in 6 months may try to burn the Mac OS X 10.7 (Lion) installer to a DVD and find their optical drive is broken. \u00a0This might lead to the update being blamed, even though the drive could have been broken at any point in that 6 month period without the user noticing.<\/p>\n Understanding the causes is all very well and good, but the average user with problems doesn\u2019t care about all that. \u00a0He\/she just wants to have a working computer again! \u00a0So what can you do if your system is having problems following an update or upgrade?<\/p>\n Note that, before you attempt any of the following fixes, you should have a good set of up-to-date\u00a0backups<\/a>!<\/p>\n Many problems can be traced to one of these things. \u00a0Your Mac requires that you keep roughly 10% of the hard drive free. \u00a0You can check these numbers by selecting your hard drive in the Finder and choosing File -> Get Info. \u00a0In the window that appears, compare the Capacity and Available values. \u00a0If you have a drive with a total capacity of 500 GB, your available space should not fall below 50 GB.<\/p>\n If you don\u2019t have enough free space on your hard drive, your computer will begin to slow down, may start crashing and, if space gets tight enough, may even corrupt data. \u00a0The fix is easy, fortunately\u2026 \u00a0delete some stuff! \u00a0You will either want to get an external drive and move some of your data to that or replace the internal drive with a larger one. \u00a0The former is a quick and easy solution for anyone, while the latter is not a do-it-yourself project for everyone and will take more time. \u00a0In any case, though, you\u2019ve gotta free up some hard drive space!<\/p>\n If you don\u2019t have enough RAM, that can cause your machine to slow to a crawl and make the spinning beach ball cursor a common sight. \u00a0Mac OS X 10.7 (Lion) in particular is very demanding when it comes to RAM. \u00a0Fortunately, there\u2019s an easy check to see if you\u2019re having RAM-related performance problems. \u00a0When you start having problems, open Activity Monitor (in \/Applications\/Utilities), click the System Memory tab and compare the page ins and page outs. \u00a0If page outs is 10% or more of the page ins, you need more RAM. \u00a0So, for example, if the page ins value is 500 MB and page outs is 50 MB, you probably need more RAM. \u00a0(The higher the page outs, the more desperately you need more RAM.) \u00a0However, if page outs is only 5 or 10 MB, you\u2019re fine.<\/p>\n If that test indicates that you need more RAM, you have two options. \u00a0First, you can start being more cautious about what apps you are running at the same time. \u00a0That may not be sufficient if you use particularly \u201cheavy\u201d apps, though. \u00a0The other choice is to buy more RAM. \u00a0You\u2019ll get a better price if you buy from a company like\u00a0Crucial<\/a>\u00a0or\u00a0Other World Computing<\/a>\u00a0and install the RAM yourself. \u00a0But if that intimidates you, pay the premium to buy it from Apple and have one of their techs install it for you.<\/p>\n If you are not having\u00a0kernel panics<\/a>, you can skip this step.<\/p>\n Kernel panics are usually caused by one of two things: bad third-party kernel extensions (kexts) or hardware problems. \u00a0The\u00a0kernel panic logs<\/a>\u00a0can help you determine the cause. \u00a0Open the latest log and search for a line that reads \u201cloaded kexts:\u201d, and look directly below that for any lines that don\u2019t start with \u201ccom.apple.\u201d \u00a0Also look at what appears directly below the line reading \u201cKernel Extensions in backtrace:\u201d, to help narrow things down. \u00a0If you recognize the names of any software you have installed in either of those places, try removing that software.<\/p>\n If you don\u2019t see any third-party kernel extensions mentioned in the log, you may have a hardware problem. \u00a0You should run the rest of the tests, but be prepared to call Apple for service.<\/p>\n Open Disk Utility, select your hard drive (the one the system is on if you have more than one) and click the Repair Disk Permissions button in the First Aid tab. \u00a0That will probably not help anything, but sometimes it does, and it\u2019s a quick and easy thing to try. \u00a0Note that there are a number of messages that will appear every time and that can be ignored\u2026 \u00a0see\u00a0Apple\u2019s document on permissions messages<\/a>\u00a0for more information.<\/p>\n Next, you need to repair the hard drive, following Pondini\u2019s instructions here:<\/p>\n http:\/\/pondini.org\/OSX\/DU6.html<\/a><\/p>\n If problems are found that cannot be repaired, you\u2019ll need to either erase the hard drive and restore the system from a backup or try repairing with another tool, like\u00a0Disk Warrior<\/a>.<\/p>\n Of course, even if you get all the repairs done successfully, that does not necessarily mean your problems will go away. \u00a0A damaged hard drive can easily lead to corrupted data somewhere, so you\u2019ll probably still need to keep chugging through these steps. \u00a0But at least you won\u2019t be worsening the problem by continuing to use a damaged drive!<\/p>\n Oh, and one other note: if you still see your problems even when you have started up from the recovery partition or Mac OS X install disk, chances are good that it\u2019s hardware. \u00a0You can certainly run the rest of these tests if you like, but I personally would take my machine to the nearest Apple Store ASAP, and would probably skip ahead to step 8 just to see if a hardware issue could be identified easily.<\/p>\n Mac OS X allows you to start up in\u00a0Safe Mode<\/a>\u00a0by holding down the shift key at startup. \u00a0One of the things that Safe Mode does is disable all third-party software that runs at startup. \u00a0This test can tell you if problems are caused by third-party software. \u00a0If problems go away during Safe Mode, but come back as soon as you have restarted normally, then they\u2019re almost certainly caused by third-party software. \u00a0The trick will then be sorting through all your software to find the culprit. \u00a0Once you have found the cause, you should check to see if a newer version is available, offering compatibility with the new system. \u00a0If the developer does not offer an update, you\u2019ll have to either replace the software or revert to an older system (not an easy or fun task).<\/p>\n If the problem goes away after starting up in Safe Mode, even after you reboot normally, then it may have simply been a cache-related problem or something else along those lines. \u00a0See the information about Safe Mode on Apple\u2019s web site for more information about other things Safe Mode does.<\/p>\n Corruption of settings files in your account\u2019s home folder can cause all manner of strange problems. \u00a0Open System Preferences (from the Apple menu), then click Accounts (in Mac OS X 10.6 or earlier) or Users & Groups (in Mac OS X 10.7). \u00a0Click the lock in the bottom left corner of the window to allow you to make changes (you will need an administrator account username and password). \u00a0Then click the + button below the user list. \u00a0Create a new user (a \u201cStandard\u201d account is sufficient).<\/p>\n Now log out and log in as the new user. \u00a0Run some tests and try to get your problems to happen. \u00a0If they still occur, the problem has nothing to do with one particular user, and you can skip to the next step. \u00a0If they don\u2019t, the problem is specific to your user account. \u00a0Now you just have to try finding the cause. \u00a0One thing to try, if your user account is an admin user, would be to log back in to your regular account and execute the following command in the Terminal (found in \/Applications\/Utilities):sudo plutil -s ~\/Library\/Preferences\/*.plist<\/p>\n (Copy and paste it rather than trying to re-type it.) \u00a0When you hit return, you\u2019ll be prompted for your account password\u2026 \u00a0don\u2019t be startled when typing doesn\u2019t display anything, that\u2019s normal. \u00a0Hit return again, then wait until the Unix prompt reappears. \u00a0If nothing else is printed on the screen, it didn\u2019t find any corrupt preferences (though that\u2019s no guarantee).<\/p>\n Clearing caches is not something that should be done for regular maintenance, as some people will tell you. \u00a0Caches are there to help keep things running fast. \u00a0However, sometimes caches can become corrupt, and this can cause all manner of strange behavior, including application crashes. \u00a0If the previous fixes haven\u2019t helped, it\u2019s time to try clearing the caches. \u00a0There are a number of utilities that can help you do this, some good and some best avoided. \u00a0To be safe, I recommend simply doing the job yourself. \u00a0You can safely delete everything in the following folders:~\/Library\/Caches \/Library\/Caches<\/p>\n The first of those is found in the user Library folder (which is invisible in Mac OS X 10.7), while the second is found at the root level of the hard drive. \u00a0If that\u2019s Greek to you, just choose Go -> Go to Folder in the Finder and paste in the first path, then hit return. \u00a0Delete everything inside that folder. \u00a0Then repeat with the second folder. \u00a0Once you\u2019re done, restart the computer.<\/p>\n One caution: any time you delete stuff like this from your computer, it would be wise to have a good set of\u00a0backups<\/a>, just in case something goes wrong.<\/p>\n If this is too intimidating to try to do manually, download\u00a0OnyX<\/a>\u00a0and use it to clear the caches.<\/p>\n This is not a solution that should be applied to all problems. \u00a0But if you\u2019re having trouble with sleep, starting up or shutting down, excessive fan speed or heat, battery issues or other similar problems, you should try following\u00a0Apple\u2019s instructions to reset the SMC<\/a>.<\/p>\n PRAM, aka Parameter RAM, is a chip that maintains certain settings on the machine \u2013 things like clock settings, the selected beep sound, speaker volume, key repeat rates, etc. \u00a0This is kind of a last-ditch effort, a bit like sacrificing a chicken at the altar of the technology gods, but it can help in certain cases. \u00a0To reset the PRAM, start up the computer and immediately press and hold command-option-P-R. \u00a0When the computer restarts and you hear the startup chime a second time, you can release the keys.<\/p>\n I\u2019ll be honest, though\u2026 \u00a0I haven\u2019t zapped the PRAM on any of my Macs in more than a decade. \u00a0I only offer this as something to try because it\u2019s quick and easy, and has been known to fix some things, but not because it\u2019s likely to help in most cases.<\/p>\nSolving the Problems<\/h2>\n
Step 1: Check the hard drive and the RAM<\/h3>\n
Step 2: Examine kernel panic logs<\/h3>\n
Step 3: Repair permissions and the hard drive<\/h3>\n
Step 4: Start up in Safe Mode<\/h3>\n
Step 5: Test a new account<\/h3>\n
Step 6: Clear caches<\/h3>\n
Step 7: Reset the SMC<\/h3>\n
Step 8: Zap the PRAM<\/h3>\n
Step 9: Run Apple Hardware Test<\/h3>\n