Once again, the Redmond giant "surprises" users of its flagship operating system with problems in its patches. On February 9 was the classic Patch Tuesday, and one of the updates received by Windows 10 carries the name KB3135173, which fixes at least eight reported vulnerabilities. Unfortunately, many users discovered that the brand-new hotfix applies a reset to several file associations, reverting their configuration to Microsoft's factory apps, and preventing subsequent modifications.
Finding a bug in a patch is nothing new, but with the new policy of mandatory updates that Microsoft decided to implement under Windows 10, user headaches have multiplied. It is evident that Redmond is going through a weak phase regarding the quality control of its hotfixes, and although we hope it overcomes it soon, that seems a bit far off. The latest news points to the hotfix identified as KB3135173, intended for Windows 10 1511 installations, that is, those that received a large cumulative patch in mid-November. This hotfix is somewhat relevant because it fixes at least eight vulnerabilities, spread across Microsoft Edge, Internet Explorer, WebDAV, and .NET Framework.
Being a security hotfix, the first thing that comes to mind is allowing its installation immediately, but in recent days, multiple reports indicate that this update applies a general reset to the most important file associations, reverting all configuration to the preinstalled applications in Windows 10. This also affects programs predefined for actions such as navigation, email, and music playback. For example, users who prefer tools like SumatraPDF or Adobe Reader to view PDF documents discovered that after the update, Microsoft Edge was the application defined by the system. As if that were not enough, every time they tried to undo that change and reconfigure their apps, the Action Center presented a warning in which "an application has caused a problem" and blocked the operation.
The most logical solution for affected users is to uninstall the update, or roll back to a previous state with the help of System Restore, but that does not prevent Windows Update from downloading and installing the defective hotfix again. In that case, what is recommended is to obtain the tool under identifier KB3073930, which allows temporarily blocking updates. Alternatively, the people at the Winhelponline blog have put online a Registry hack that prevents Windows applications from "hijacking" file associations. It's dirty work, but with Windows 10's mandatory updates, we wouldn't expect anything less.
