Many users prefer updating their Mac computer with a combo installer instead of using Software Update within OS X. However, some users get confused when an update is not accompanied by a combo installer.
Combo installers for OS X updates are an infamous solution to a wide variety of problems. These installers can potentially fix issues because they will overwrite files from prior updates that might not have installed correctly or that may have become corrupted.
Believing in the combo installer’s ability to correct issues, many users swear by updating through this method only and thus avoid using the standard software update methods ever. However, in many circumstances combo installers are not released by Apple, and I see several tweets and emails begging “where is the combo installer?”
Combo installers will never be released with the first update to a new OS version. For example, 10.8.0 Mountain Lion was recently released, and the 10.8.1 update soon followed. As there is only one update to the 10.8 line, no combo installer is possible. There is no combination of updates to combine!
X.Y.0 – Original Release
X.Y.1 – First Update. No combo installer is possible.
X.Y.2 – Second Update. Combo installer would update X.Y.0 and X.Y.1 to X.Y.2.
X.Y.3 – Third Update. Combo installer would update X.Y.0 through X.Y.2 to X.Y.3.
etc.
Apple has released OS X updates like this for as long as I can remember.
Since combo installers are typically downloaded, some people also use the name “combo installer” incorrectly as a way to describe a downloaded update versus an update that occurs automatically through the Software Update application in OS X. Download updates are especially helpful when updating many systems such as in an enterprise environment. Even though a combo installer update is not available for every update release, all updates can still be downloaded directly through Apple, even with X.Y.1 updates.
