Microsoft KB Archive/254019

= "Unable to Create Symbolic Link" Error Message When Installing a Modem on a COM Port =

Article ID: 254019

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition

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This article was previously published under Q254019



SYMPTOMS
After you install a modem on a COM port, you may receive the following error message in Event Viewer:

Unable to create symbolic link for COM

This problem can occur with any COM port listing.



CAUSE
This behavior can occur if you are using an incorrect I/O address or IRQ.



RESOLUTION
To resolve this issue, use the appropriate method.

Method 1: Remove the COM Port and Let Windows NT Redetect the Port

 * 1) Start the Ports tool in Control Panel.
 * 2) Click the COM port listing, and then click Delete.
 * 3) Click OK, and then click Close.
 * 4) Restart Windows NT.

Method 2: Change the I/O Address or IRQ of the COM Port

 * 1) Start the Ports tool in Control Panel.
 * 2) Click the COM port listed in the error message.
 * 3) Click Setting.
 * 4) In the Inside Setting for COM  section, click Advanced.
 * 5) Change the BASE I/O Port Address to a location that you are not using.

NOTE: You can refer to Windows NT diagnostics to find out which I/O port addresses are in use. By default, COM1 uses 03F8-03FE, and COM2 uses 02F8-02FE.

Method 3: Change the IRQ

 * 1) Start the Ports tool in Control Panel.
 * 2) Click the COM port listed in the error message.
 * 3) Click Setting.
 * 4) In the Inside Setting for COM  section, click Advanced.
 * 5) Change the COM port to an IRQ that you are not using.

NOTE: You can refer to Windows NT diagnostics to find out which I/O port addresses are in use. By default, COM1 uses IRQ 4, and COM2 uses IRQ 3.

Keywords: kberrmsg kbprb KB254019

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