After rebooting for upgrades on Saturday 2017-10-14, many or perhaps all Windows Store -installed apps stopped working on my win10 pro computer. They all show an error dialog similar to this one, from Edge's 1Password addon:
The English form of the localized error message is
The specified user does not have a valid profile.
Can't really find anything on Google about anybody having this specific issue, there are some articles about fixing broken profiles but those instances talk about being unable to log in. I have no such issue. Apart from these Store app problems, the only other symptom is that I am unable to set Edge as my default browser. Instead of Edge, the browser selector in the settings app shows an entry labeled "Launch Windows App" with an Edge icon, but then links just don't work. Reinstalling Store apps does not fix the problem.
Edited to add: The latest updates installed on the machine seem to be "2017-10 Cumulative Update for Windows 10 Version 1703 for x64-based Systems (KB4041676)" and "Windows Malicious Software Removal Tool for Windows 8, 8.1, 10 and Windows Server 2012, 2012 R2, 2016 x64 Edition - October 2017 (KB890830)".