Microsoft has announced that a bug in the Windows 10 1809 USB Type-C Connector System Software Interface (UCSI) software implementation can cause the operating system to shut down slower under certain situations.

According to Microsoft, if you plug in or disconnect a USB Type-C device, whether that be a docking station, a charger, or a device, while the computer is powering down, it will cause it to take 60 seconds longer than normal.

"My system takes a long time to power down if a USB Type-C device, dock, or charger is plugged in or unplugged during the power transition. A bug in the USB Type-C Connector System Software Interface (UCSI) software implementation in Windows 10, version 1809 can cause a 60 second delay in the system sleep or shutdown process if the power-down happens while the UCSI software is busy handling a new connect or disconnect event on a USB Type-C port. Apart from the extra one minute the sleep or shutdown process takes in this circumstance, this bug does not affect normal functionality of USB Type-C on your machine. The system and the USB Type-C ports should continue to function properly after the next wake or restart of the system."

On reboot, as long you do not perform the same behavior, the shutdowns will perform at normal speed.

Microsoft has also stated that this bug does not cause any issues with the normal functionality of the plugged in device, but it is just a bug related to connecting or disconnecting a device during a power down event.

Based on an issue listed in the Windows 10 Feedback Hub, this bug appears to have been discovered internally by Microsoft engineer approximately 2 weeks ago.

Feedback Hub

If you are using Windows 10 v1809, the general recommendation is to not disconnect or connect a USB Type-C device while performing a shut down. Instead do this before the shutdown is initiated or after.

For Windows 10 1903 users, this issue has been fixed in that version and you do not need to worry about it.