For about a year, I couldn’t use any Windows 10 apps or Xbox games that required me to sign in with a Microsoft Account. I also couldn’t add any email or other online accounts to my Windows account. For whatever reason, all the Microsoft Accounts Control and Windows Web Account Provider dialog windows refused to open. Whenever I clicked a button that was supposed to open these dialogs, I might see a brief white flash that hinted at the brief appearance of a dialog window. Most of the time, absolutely nothing happened. Deep-rooted problems with Windows are incredibly difficult to troubleshoot. When developing its software, Microsoft always assumes everything will work flawlessly all the time. Apps and system services rarely generate log files, report errors to the Events system, or even record diagnostics data about the problem. The Diagnostics Viewer reported to Microsoft that I’d opened the desired dialog for less than a millisecond ...