Failed to initialize COM library module in CICON

Q. How to solve
an issue when you cannot connect to CICON via USB, Serial 
and Ethernet ports and get an error

“Failed to
initialize the COM library module.

 Please check whether the port was already
occupied by other program.”

A. This error occurs when the following four COM library
module files are not properly registered on your PC due to the absence of
“Microsoft Visual C++ 2008 Redistributable Package (x86).”

▶ When
you cannot make a connection between CIMON PLC and CICON software via USB,
Serial and Ethernet ports, you need to check on three things:

1. Did
you install “Microsoft Visual C++ 2008 Redistributable Package (x86)?”

2. Is USB
driver for CICON or Serial driver recognized in Device Manager?

3. Did
you change the location or name of the CICON installation folder?

software has been built on Visual C++ 2008 and 32-Bit. No other versions are
acceptable except the “Microsoft Visual C++ 2008 Redistributable Package (x86).
Please download the package directly from Microsoft.


▶ If
properly installed, CIMON PLC USB driver should be recognized in Device


  • 64bit:
    CIMON PLC USB Driver for CICON
  • 32bit:

▶ Also, check
your Serial Port (COM) number in Device Manager for serial connection.
▶ Once
the CICON installation location is fixed at the below photo, the location and
name of the installation folder must not be changed after the installation.
  • For
    instance, the location has been decided to be “CCIMONCICON”

  • Do not
    move the location of the installation folder to somewhere else.
  • i.e.
    Local Disk (D:)
    → SOFTWARE → CICON → CICON6.00 En_20150701