The modem does not work and you cannot open the "Network Connections" window after you unplug and plug in the modem several times when a PPP connection is established in Windows XP


Consider the following scenario:
  • You establish a Point-to-Point Protocol (PPP) connection over a USB modem on a computer that is running Windows XP.
  • You unplug, and plug in the USB modem several times.
In this scenario, you find the CPU usage becomes very high in Task Manager, and the computer stops responding when you try to open the Network Connections window. Also, the modem does not work after it is plugged in again. Sometimes, this may cause the computer to restart.


This issue occurs because of a problem in the Unimdm.tsp file.


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.


To apply this hotfix, you must have Windows XP Service Pack 3 (SP3) installed on the computer.

Restart requirement

You have to restart the computer after you apply this hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) 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 item in Control Panel.

For all supported x86-based versions of Windows XP SP3

File nameFile versionFile sizeDateTimePlatform
Unimdm.tsp5.1.2600.5815206,84819-May-200921:29Not Applicable


To work around this issue, you must restart the computer.


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

More Information

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates


Article ID: 970254 - Last Review: Feb 15, 2017 - Revision: 2

Microsoft Windows XP Home Edition, Microsoft Windows XP Professional