Windows processes cannot access a serial port after an Interix process uses the serial port


After an Interix process uses a serial port and then closes, Microsoft Windows processes cannot access the serial port.

For example, after the Igetty process uses a serial port and then closes, the HyperTerminal process cannot access the serial port.


Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


No prerequisites are required.

Restart requirement

You must restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix replaces:
838250 FIX: The POSIX subsystem for Interix does not start successfully after Windows Server 2003 Service Pack 1 (S838250) is installed

This hotfix is replaced by:
841898 FIX: You cannot create more processes when many Win32 processes are called from Interix

File information

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version            Size    File name
30-Apr-2004 22:41 8.0.1969.5 763,904 Psxss.exe


To work around this problem, release the serial port. To do this, stop the Interix Subsystem Startup service.

To restart the Interix Subsystem Startup service, restart the computer.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

Article ID: 841066 - Last Review: May 28, 2008 - Revision: 1