We will file this item under 'Why has this taken so long?'
Microsoft filed a patent that describes a process for repairing corrupt software. The patent goes far beyond the traditional System Restore in Windows and uses a download capability to fix a software problem. Conceivably, this could be a critical milestone toward the achievement of an operating system that largely maintains itself and does not surprise its user with a note that some file is missing and that Windows isn't able to boot as a result. Windows has been prone to such problems especially during OS upgrade processes and even simple software updates that, for example, affected some Windows Vista SP2 users who tried upgrading IE8 to IE9.
The patent application, filed in December 2010, states that Windows may be able "to resolve problems that occur when corrupt software is updated by allowing a corrupt component to be repaired and then uninstalled such that an updated component can be properly installed." It is a pretty straight-forward approach that uses "the smallest amount of data necessary to repair the identified corruption." According to the filing, the validation of a repair file would be done via a secure hash key.
Microsoft also envisions this technology will run semi-autonomously. While a user can initiate a "corruption scan," the OS can also initiate the repair service by itself when an error message is received from the software updating service that could, for example, include a malware warning. A successful repair would also run automatically and check "whether all of the corrupt software components have been updated." Based on the success or failure of the update, additional file replacements can take place, if needed.
The patent application does not provide any information on what the repair service would do if the attempt to replace a corrupt file fails.