Apple routinely releases updates to OS X that are available through the software update process or the Mac App Store, depending on the version of OS X you’re using. These software updates, available from the Apple menu, often offer the easiest method of ensuring your Mac’s operating system stays up to date. They can also cause problems, especially if your Mac freezes, loses power, or prevents the update from completing. When this happens, you end up with a corrupt system update, which can manifest as simple instability: occasional freezes or system or application crashes. In the worst case, you may have trouble booting,
Another issue is related to OS X’s incremental approach to updates. Since Software Update only downloads and installs system files that need to be updated, some files may not be up to date with other system files. This may cause the system or application to freeze infrequently, or an application to fail to start.
Although the software update issue is rare and most Mac users will never see it, if you’re experiencing unexplained problems with your Mac, the software update issue could be to blame. Eliminating it as a possibility is very easy to do.
Using the OS X Combo Update
You can use the OS X Combo Update to update your system and, in the process, replace most of your key system software files with the latest versions included in the updater. Unlike the incremental approach used in system software updating, the combo update performs a complete update of all affected system files.
The combo only updates OS X system files; it does not overwrite any user data. That said, it’s still a good idea to back up before applying any system updates.
The downside to combo upgrades is that they are huge. The current update (at the time of this writing) for Mac OS X 10.11.3 Combo Update is less than 1.5 GB. Future OS X combo updates are bound to be even bigger.
To apply a Mac OS X Combo Update, find the file on Apple’s website, download it to your Mac, and then run the update, which will install the latest system on your Mac. You can’t use a Combo Update to unless the baseline of that version of OS X is already installed. For example, the Mac OS X v10.10.10.2 (merge) update requires that OS X 10.10.0 or later is already installed. Also, the Mac OS X v10.5.8 (combination) update requires OS X 10.5.0 or later to be installed.
Locate the OS X Combo update you need
Apple keeps all OS X Combo updates available on Apple’s support site. A quick way to locate the correct combination update is to visit the OS X Support Download site. There you’ll see the three most recent versions of OS X, along with a link to earlier versions. Click the link for the version you’re interested in, then set the view option to Alphabetical and scan the list for the combo update you need. All combo upgrades will have the word “combo” in their names. If you don’t see the word combo, it’s not the full installer.
Here are quick links to the most recent (at the time of writing) combo updates for the last five versions of OS X:
OS X Version Download Page macOS High Sierra 10.13.4 Combo Update macOS High Sierra 10.13.3 Combo Update macOS High Sierra 10.13.2 Combo Update macOS Sierra 10.12.2 Combo Update macOS Sierra 10.12.1 Combo Update OS X El Capitan 10.11. 5 OS X El Capitan 10.11.4 Combo Update OS X El Capitan 10.11.3 Combo Update OS X El Capitan 10.11.2 Combo Update OS X El Capitan 10.11.1 Combo Update OS X Yosemite 10.10.2 Combo Update OS X Yosemite 10.10.1 Combo Update OS X Mavericks 10.9.3 Update OS X Mavericks 10.9.2 Combo Update OS X Mountain Lion 10.8.5 Combo Update OS X Mountain Lion 10.8.4 Combo Update OS X Mountain Lion 10.8 Combo Update. 3 OS X Mountain Lion 10.8.2 Combo Update OS X Lion 10.7 Combo Update.5 OS X Snow Leopard 10.6.4 Combo Update OS X Leopard 10.5.8 Combo Update OS X Tiger 10.4.11 Combo Update (Intel) OS X Tiger 10.4.11 Combo Update (PPC) OS X Combo Update Update of Combo Downloads
Combo updates are stored as .dmg (disk image) files that will be mounted on your Mac like removable media, such as a CD or DVD. If the .dmg file doesn’t mount automatically, double-click the downloaded file that you saved to your Mac.
Once the .dmg file is mounted, you will see a single installation package. Double-click the installation package to start the installation process and follow the on-screen prompts.
