It happened with the recent 12.1.3 update to Microsoft Office 2008. It will inevitably happen again with the just-released 12.1.4 update. In fact, it's a long-standing glitch in Microsoft's update process, one that plagued numerous versions. What happens is this:
The Microsoft AutoUpdate application notifies you that an update is available. You select to download it and run the Installer. And that's about as far as you go. The Installer complains "No version of the software found on volume" and the installation halts. You scratch your head, fully aware that the relevant software is indeed available, and wonder what went wrong.
The most likely cause is that, to save disk space, you previously removed unwanted language-specific files in Office. You can do this with utilities such as Macaroni. Having done this, the Microsoft Installer no longer recognizes the Office software as updatable.
If this describes your situation, the most straight-forward solution, albeit a time-consuming one, is to reinstall your initial version of Office and re-update, this time without deleting the language files.
A reader comment on VersionTracker, however, suggests a quicker but riskier work-around (as I have not tried it and cannot confirm it works):
MacInTouch has posted an e-mail from Microsoft Technical Support that offers some other potential causes and solutions for this symptom. Most notably, it claims that the symptom may be triggered either by having an external drive attached or by having Parallels software running. If so, the obvious suggested solution is to disconnect the external drive and/or quit Parallels.
By the way, the new 12.1.4 update is a minor one that appears to address just one specific bug: "This update fixes a calendar issue in versions of Microsoft Entourage that were updated with the Microsoft Office 2008 for Mac 12.1.3 Update. The issue prevents Exchange accounts in Entourage from sending meeting invitations and responses. This issue can occur when an Entourage identity is configured with more than one mail account." In other words, installing the 12.1.4 update requires that you have first installed the 12.1.3 update (the version that causes the problem).
This story, "Bugs & Fixes: When Updating Microsoft Office Fails" was originally published by Macworld.