What is the serial enumeration driver and why would I need it?
The serial enumeration driver (serenum) is a filter driver that sits on top of the Virtual COM Port driver (silabser). Its purpose is to detect when a device sends an ‘M’ character upon enumeration and enumerate that device as a mouse rather than a regular COM port.
Most applications will not need this portion of the driver to be installed on the system, and it can cause issues when the hardware connecting to the Windows PC sends a constant steam of characters and one of those characters can be 'M'. When this happens, the hardware connected to the PC will mistakenly enumerate as a mouse and cause the mouse cursor to behave erratically.
If the serial enumeration driver functionality is not required by the application, the VCP installer package without the serial enumeration driver can be used. This should be the case in most applications.
More information on serenum can be found in MSDN here: https://msdn.microsoft.com/en-us/library/windows/hardware/ff546505(v=vs.85).aspx.