OSX Tips
Installing the "combo" update and/or Reinstalling OSX
The procedures are somewhat different depending on what "major version" of OSX you're on, Lion, Snow Leopard or Leopard (sorry, earlier versions of OSX aren't covered here).
(If you're not sure what version of OSX you're running, click here).
Snow Leopard 10.6.x
"COMBO" UPDATE
If your installation of OSX is corrupted or damaged, you may want to start by downloading and installing the appropriate "combo" update. It contains all the updates since the first release of Snow Leopard (thus the clever name). Instructions and downloads are here:
(Note: there's a separate Snow Leopard 10.6.8 Supplemental Update: http://support.apple.com/kb/HT1429 that is not included in the 10.6.8 "combo".)
Snow Leopard 10.6.8: http://support.apple.com/kb/DL1399
Snow Leopard 10.6.7: http://support.apple.com/kb/DL1361
Snow Leopard 10.6.6: http://support.apple.com/kb/DL1349
Snow Leopard 10.6.5: http://support.apple.com/kb/DL1324
Snow Leopard 10.6.4: http://support.apple.com/kb/DL1048
Snow Leopard 10.6.3: http://support.apple.com/kb/DL1017
Snow Leopard 10.6.2: http://support.apple.com/kb/DL959
Snow Leopard 10.6.1: http://support.apple.com/kb/DL930
Be sure to do a Repair Permissions afterwards, per Verify or Repair Disk Permissions.
The next Time Machine backup will be somewhat larger than normal, to back up the changes.
Note: after installing the update, don't delete it immediately; if it doesn't fix your problem, you may want to reinstall OSX and perhaps apply the "combo" again.
REINSTALLING OSX
Effective with Snow Leopard, there's only one Install option, and it shouldn't disturb any of your apps, data, etc., but there’s always a risk of something going wrong, so be sure you have good backups before starting. Many folks recommend not only Time Machine backups, but also a "secondary" backup, just in case something goes wrong with the drive they’re on, or Time Machine itself. See Time Machine FAQ #27 for some suggestions.
First, turn Time Machine OFF. It’s a good idea to eject and disconnect your Time Machine drive, too. Ditto any other external drives, just in case.
Ensure that your Mac has uninterrupted AC power.
Start your Mac from your Snow Leopard Install disc. Insert it into your SuperDrive, then either wait for the Mac OS X Install DVD window and double-click the Install icon; or power down, then start up normally while holding down the "C" key. That takes a few minutes.
Select your language, at the Welcome screen click Continue, then Agree to the license.
In the window where you select a disk, select your current Mac OS X disk (in most cases, it will be the only one available, and named Macintosh HD).
•Click Customize if you need to select or deselect optional software.
You can customize some of the software that will be installed, such as printer drivers, fonts, and language translations. In the Custom Install pane, select the software you want to install, and then click OK.
•Click Install.
Once your Mac reboots after the installation completes, you’ll probably need to install the appropriate "combo" update again to get back to the version of OSX you were on, or use Software Update.
(The next backup will be somewhat larger than usual, to back up the new version of OSX.)
Leopard 10.5.x
"COMBO" UPDATE
If your installation of OSX is corrupted or damaged, start by downloading and installing the appropriate "combo" update. It contains all the updates since the first release of Leopard (thus the clever name). Instructions and downloads are here:
Leopard 10.5.8: http://support.apple.com/downloads/Mac_OS_X_10_5_8_Combo_Update
Earlier versions: just change the "8" in the link above to the desired one.
Be sure to do a Repair Permissions afterwards, per Verify or Repair Disk Permissions.
The next Time Machine backup will be somewhat larger than normal, to back up the changes.
Note: after installing the update, don't delete it immediately; if it doesn't fix your problem, you may want to reinstall OSX and perhaps apply the "combo" again.
REINSTALLING OSX shouldn’t disturb any of your apps, data, etc., as long as you select the correct option (see below), but there’s always a risk of something going wrong, so be sure you have good backups before starting. Many folks recommend not only Time Machine backups, but also a "secondary" backup, just in case something goes wrong with the drive they’re on, or Time Machine itself. See Time Machine FAQ #27 for some suggestions.
First, turn Time Machine OFF. It’s a good idea to eject and disconnect your Time Machine drive, too. Ditto any other external drives, just in case.
Ensure that your Mac has uninterrupted AC power.
Start your Mac from your Leopard Install disc. Insert it into your SuperDrive, then either wait for the Mac OS X Install DVD window and double-click the Install icon; or power down, then start up normally while holding down the "C" key. That takes a few minutes.
Select your language, at the Welcome screen click Continue, then Agree to the license.
In the window where you select a disk, select your current Mac OS X disk (in most cases, it will be the only one available).
LEOPARD has two Install options. Be sure you pick the right one:
•Click Options in the lower left, choose Archive and Install, ensure that Preserve Users and Network Settings is checked, then click OK.
•Back at the Select a Destination screen, click Continue.
•At Install Summary, click Install.
Once your Mac reboots after the installation completes, you’ll probably need to install the appropriate "combo" update again to get back to the version of OSX you were on, or use Software Update.
(The next backup will be somewhat larger than usual, to back up the new version of OSX.)
There will be a Previous System folder at the top level of your internal HD, containing a copy of the previous installation. This is just in case something didn't transfer properly. Either delete it before the next backup, or exclude it from Time Machine backups, per Time Machine FAQ #10.
Note that emptying the trash after deleting it will take a very long time.
Lion 10.7.x
Usually it's best to just get the update from the App Store. If that's a problem, you can get the download from here:
"COMBO" UPDATE
If your installation of OSX is corrupted or damaged, you may want to start by downloading and installing the appropriate update. Instructions and downloads are below (but if you're running Lion Server, see http://support.apple.com/downloads#macos):
Lion 10.7.5 http://support.apple.com/kb/DL1582 (includes "10.7.5 supplemental update")
Lion 10.7.4 http://support.apple.com/kb/DL1524
Lion 10.7.3 Supplemental Update http://support.apple.com/kb/DL1505
Lion 10.7.3 http://support.apple.com/kb/DL1484
Lion 10.7.2 http://support.apple.com/kb/DL1459
Lion 10.7.1 http://support.apple.com/kb/DL1437
Lion 10.7.1 for MacBook Air and Mac mini 2011 http://support.apple.com/kb/DL1439
Be sure to do a Repair Permissions afterwards, per Verify or Repair Disk Permissions.
The next Time Machine backup will be somewhat larger than normal, to back up the changes.
Note: after installing the update, don't delete it immediately; if it doesn't fix your problem, you may want to reinstall OSX and perhaps apply the "combo" again.
REINSTALLING OSX
If you have an OSX USB thumb drive, start up from it: connect it and start while holding the Alt/Option key. After a few moments, you'll get a display showing all bootable drives. Select it. When it starts, select Install Mac OS X, and follow the on-screen instructions.
If you have a Lion Install disc or partition, start up from it. If it's on a DVD, insert it and start up while holding down the "C" key. If it's on a partition, either select it via System Preferences > Startup Disk, or start up while holding down the Alt/Option key; that will show all the possible startup sources. Select the one you want.
If you don't have any of those, you'll have to download a fresh copy of OSX, via the Reinstall Mac OSX section of Using the Recovery HD. Note that this is the most current version of Lion; you can't go back to an earlier version.
When it starts up, you'll see the main Installer window: click the Continue icon, and agree to the license. The next window shows the default install location; usually your internal HD. If you wish to install it elsewhere, click Show All Disks to get a list you can select from.
(The next backup will be somewhat larger than usual, to back up the new version of OSX.)
Mountain Lion 10.8.x
Usually it's best to just get the update from the App Store. If that's a problem, you can get the download from here:
"COMBO" UPDATE
Mountain Lion 10.8.4 http://support.apple.com/kb/DL1659
Mountain Lion 10.8.3 http://support.apple.com/kb/DL1640
Mountain Lion 10.8.2 supplemental update 2.0: http://support.apple.com/kb/DL1611
Mountain Lion 10.8.2 supplemental update: http://support.apple.com/kb/DL1600
Mountain Lion 10.8.2 http://support.apple.com/kb/DL1581
Mountain Lion 10.8.1 http://support.apple.com/kb/DL1571
REINSTALLING OSX
If you made a Mountain Lion Install disc or partition, start up from it. If it's on a DVD, insert it and start up while holding down the "C" key. If it's on a partition, either select it via System Preferences > Startup Disk, or start up while holding down the Alt/Option key; that will show all the possible startup sources. Select the one you want.
If you don't have any of those, you'll have to download a fresh copy of OSX, via the Reinstall Mac OSX section of Using the Recovery HD. Note that this is the most current version of Mountain Lion; you can't go back to Lion or an earlier version of Mountain Lion.
When it starts up, you'll see the main Installer window: click the Continue icon, and agree to the license. The next window shows the default install location; usually your internal HD. If you wish to install it elsewhere, click Show All Disks to get a list you can select from.
(The next backup will be somewhat larger than usual, to back up the new version of OSX.)