Applies To:
  • CitectSCADA 5.xx

This problem is specific to Windows 2000 and possibly later Windows versions. The problem is within the Windows NetBIOS implementation and causes Citect to go into an infinite state which utilises all the CPU time. It appears Citect has hung and Windows becomes extremely sluggish.

The problem occurs when Citect needs to use a network resource. This can be via protocols other than NetBIOS.

For example:

Some users have discovered that after a Windows 2000 restart they get the "hang" when they use the SQLConnect() function but then after restarting Citect the problem vanishes.


It was discovered that the problem does not eventuate as long as a connection has been made to a data source prior to starting Citect. This can be done through the DSN test facility in the ODBC administration of Windows. Alternatively, a work-around has been implemented which allows a connection to be made just after starting Citect but before Citect starts initialising all its systems. This work-around can be put into affect by using the following INI parameter


where CONNECT_STRING is a valid DSN connection string in the format used by the Cicode function SQLConnect()

Citect has confirmed this to be a problem in CitectHMI/SCADA versions 5.XX. This parameter has been implemented in CitectHMI/SCADA version 5.41 to work around this problem.