Windows 10 has a new bug with the October 2018 Update, which says that shutting down a PC can take a long time, potentially over a minute, if a USB Type-C device is disconnected (or even plugged in) during the process. In a support document, Microsoft explains that the UCSI interface of the USB Type-C connector software was detected in the October 2018 update; If you turn off your PC, or if it turns off, the problem occurs if the software has to handle a new disconnect (or connect) event during the shutdown operation. If this occurs, you may have to wait 60 seconds (in addition to normal idle time) while the UCSI software collects and manages to process the Type-C device while it is disconnected or reconnected. Microsoft Notes: "Aside from the extra minute it takes to wait or shutdown in this situation, this bug does not affect normal USB Type-C functionality on your computer. The USB Type-C system and ports should continue working properly after the next activation or system reboot." So this error is not a huge problem, but it could certainly be confusing and annoying. And if you're using the October 2018 Update and recently run into a crash that seems like forever, well, at least now you know why it happened. You probably pulled out a USB key at the last second.