Freeing unused reserved COM ports in Windows 2000

How to release COM ports that Windows 2000 (XP/2003) has reserved from previous installations of COM port drivers that are no longer in use.


1. Uninstall the serial card through device manager and physically remove the card from the host.

2. Install a 'phantom' COM port.

Go to Control Panel
Add/Remove Hardware
From the Hardware Device Window select 'Add a new device'
Select 'No, I want to select the hardware...'
Highlight Ports
Select Standard Ports Types
Select Communications Port
Click OK in the 'Windows could not detect' warning window.
Select a configuration that produces no conflicts.
'Start Hardware Install'

'Restart Computer'

3. Select Administrative Tools in the Control Panel
4. Select Computer Management
5. Select Device Manager.
6. Go to Ports, (click the + to display all ports)
7. Highlight the newly created COM port (for this example we'll assume it creates COM7).
8. Right Click, select Properties.
9. Click Port Settings Tab.
10. click Advanced.
11. In the bottom left corner of the 'Advanced settings for COM x" window there is a combo box labeled "COM Port Number".
12. Open the combo box.
13. The 'missing' COM ports should be there followed by a '(in use)' tag.
14. Click on one of the ports that isn't really in use (we'll say COM4) and click OK.
15. Our 'phantom' COM7 is now labeled COM4.
16. Select 'Advanced' again and repeat the procedure, now using our 'phantom' COM4.
17. Repeat the procedure for all 'not' in use ports that you wish to free up.
18. Click OK
19. 'Restart Computer'
18. Highlight the 'phantom' port
19. Righ Click, select uninstall.
20. Uninstall the COM port.

Article ID:
1/6/2003 11:26:59 AM
Last Modified:
9/13/2004 8:30:00 AM
Issue Type:
Trouble Shooting