I just wrestled with this problem (installer/updater reporting "This volume does not meet the requirements for this update" or/and Software Update not showing updates it should) on an iBook G4, which I was trying to update from 10.4.3 to 10.4.10 using the Combo updater, and found the cause was a weird build version of OS 10.4.3 (8F1099--retail version is 8F46). Neither the Combo updater, nor Software Update, wanted to update this weird build. I don't know the source of this build--it's not my iBook, but a client's, and I doubt he would know. It might be a developer seed. In troubleshooting this problem and Googling for solutions, I compiled this list of fixes for most causes of this symptom: • What rarely fixes this problem: repairing permissions, the hard drive's directory, etc., and running any maintenance utility (including the Unix maintenance scripts (daily/weekly/monthly), but you can try these things first if you have extra time on your hands. • The problem with Software Update not showing the desired update, may be related to the installer/updater's "does not meet the requirements" symptom and its fixes listed below, but sometimes not, so first try this: 1. Delete /Library/Preferences/com.apple.SoftwareUpdate.plist. 2. In the Network prefpane, switch to a different network interface -- Ethernet instead of Airport, for instance. 3. Run Software Update. You can switch back to the original network interface once Software Update is working again. • Make sure all the requirements for the updater/installer are met: proper Mac model; any necessary hardware installed (Airport card, etc.); prior version of the software already installed, in the proper location, that's appropriate for the version you're updating (for instance, the Safari Beta 3 installer won't work unless Safari 2 is properly in place in the Applications folder); proper amount of RAM and hard drive space; etc. • Some OS X files may be missing, moved, or modified. From Frakes' & Landau's "Mac OS X Help Line, Tiger Edition": "If you have moved, deleted, or modified files in the /System/Library folder [or elsewhere], it's possible that the Installer may not recognize the OS as the correct version, even if it is. In this case, unless you can move everything back correctly, you will likely need to start over with a reinstall from a full Mac OS X [retail] Install disc." However, first run the Combo updater for the version of OS X that's currently installed, which may reinstall some missing OS X files. Of course, it may be the Combo updater itself that won't install. • The Mac may contain a pre-release or "seed" version of OS X, or some other odd build, or a server edition, or some build specific to your Mac model, and you may be trying to run an updater (probably an updater for the retail version of OS X) not compatible with these. If this is the case, the only solution is to do an Archive and Install, using a standard retail version of the OS X installer. If you have access to the discs that were used to install OS X on the Mac in question, look at their labeling, etc. to see if it mentions if it's a server, seed, Mac model specific, etc. version. To see your Mac's OS X build version, select "About this Mac" from the Apple menu, then click on the "Version" string under the "Mac OS X" title. The utility "MacTracker" contains a list of OS X's retail build version numbers, in its "Mac OS" listing--compare your Mac's build to this list. • An existing receipt file for the currently installed version of whatever you're trying to update, may be causing trouble. Receipts are located at /Library/Receipts. The quickest way to determine if this is the problem, is to move this Receipts folder into another folder so the installer/updater can't see it, then restart the Mac, and run the installer/updater again. If this works, look in the new Receipts folder that will have been created by the installer/updater, and move the receipt file it created, into your old Receipts folder that you hid, trash the older version of this receipt, then replace the new Receipts folder with the old one, then repair permissions since this moving process can mess them up. • There are a variety of more obscure causes for this problem, including version.plist files that are either damaged or contain a version number that's not accurate, or is accurate but needs to be manually changed to an earlier version, to fake out the installer/updater to allow it work, using a plist editing utility like the Apple developer software's Property List Editor. Nothing else in the main /Library folder is usually at fault for this specific symptom, so don't waste time examining it. • If all else fails, do an Archive and Install, using a standard retail version of the OS X installer.