Imagine an urgent task summoning you to your computer at an ungodly hour on a coffee-less morning; with your mind still half-way down the road from Neverland, you press a wrong key and, the next second, while you are trying to get a grasp of what is happening, the disaster is already underway. In a few minutes, everything is gone: your Windows firmly refuses to show up, presenting a non-informative BSOD in its stead, no matter how many times you press that power button.

In this series, the reader is invited to join me in a stimulating adventure of recovering an unbootable Windows system. Discarded as pointless are simple solutions such as restore points or DISM; instead, we are digging deep to the very bottom of the issue. But be warned: reaching such depths is a rather involved process; it will begin with a bugcheck analysis intended to elicit maximum information from the memory dump, a fair amount of reverse engineering (along with some static analysis) will ensue, a study of Windows registry organization and VSS operation principles will be necessary to make the best use of these technologies in the situation, and, finally, a recovery script will have to be written. There is quite a journey in store for the adventurous.

Also, the desire to share a curious investigation and the story of (albeit little) victory over one of those notoriously difficult to tackle boot-time issues is what prompted me to start the blog back in early 2019, so if one or other of my posts have proven an enjoyable read, it is to this unfortunate incident that you owe the pleasure.

This series of articles is written in the form of the case study investigating a real-life problem, that of Ubuntu Live CD suddenly failing to boot on a computer where hitherto no such problem appeared. In the premise, we are presented with an error message yielding the clue that UEFI Secure Boot might be behind the boot malfunction, while a quick online search hints at the possibility of the latest Windows update being involved. Adopting a thorough approach, we begin with a sufficiently detailed description of Secure Boot operation and its objectives, then go on to explore Windows updates in general and the kind of updates that deal with Secure Boot settings in particular. Equipped with all the necessary information, we are now in a position to design the experiment demonstrating that it was, indeed, a Windows update that caused the issue, which, of course, will involve coding.

Through a balanced presentation, including both, theory and practical demonstration, the series follows a problem-centric approach while requiring no additional research or prior knowledge of the subject to understand the material.