Serial UART Support Library (SerCx) Service Defaults in Windows 8

Serial Class Extension by Microsoft Corporation.

Default Settings

Startup type: Manual
Display name:Serial UART Support Library
Service name:SerCx
Service type:kernel
Error control:normal
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SerCx

Default Behavior

The Serial UART Support Library service is a kernel device driver. In Windows 8 it will not be started until the user starts it. If Serial UART Support Library fails to start, the error details are added to Windows 8 error log. When the operating system startup is complete, the user is being notified that the SerCx service hasn't been started.


Serial UART Support Library can't start, if the Microsoft ACPIEx Driver service is disabled or not available.

Restore Default Startup Configuration of Serial UART Support Library

Before you begin doing this, make sure that all the services on which Serial UART Support Library depends are configured by default and function properly. See the list of dependencies above.

1. Run the Command Prompt as an administrator.

2. Copy the command below, paste it into the command window and press ENTER:

sc config SerCx start= demand

3. Close the command window and restart the computer.

The SerCx service is using the SerCx.sys file that is located in the C:\Windows\system32\drivers directory. If the file is removed or corrupted, read this article to restore its original version from Windows 8 installation media.