Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.


Cannot install USB printer, "The specified port is unknown"

Cannot install USB printer, "The specified port is unknown"

I cannot install a HP Deskjet D2300-series printer.  The installation process tells me "The specified port is unknown."  I try to install manually (select a port), and the only port options are TCP/IP port and Local Port.  Where is the USB port???

The Device Manager shows that USB Printing Support is installed (looking at the device manager via Devices by Connection shows the USB printing support connected thru the USB root hub, which looks right to me).

How can I get a USB printing port to show up?  Thanks.

RE: Cannot install USB printer, "The specified port is unknown"

You should uninstall it and any copies and unplug the usb cable. Then with the computer running and printer on, plug in the cable and let XP find it. I've found that if I install a printer driver, then add the printer, I get multiple installs.

You can add the port but I only do it for remote usb printers on a print server

RE: Cannot install USB printer, "The specified port is unknown"

Except that the port IS already uninstalled.  There's another computer here with a USB printer.  When I check the ports on that computer, it lists the USB printer port as USB001, a 'virtual' printer port.  If I run the same install routine on THIS computer, that port never appears.  And, at the end of the install, I get "The specified port is unknown."  It's like the installation routine is /trying/ to connect the printer to this 'virtual' printer port, but it doesn't exist.  Anywhere.  I've already tried plugging and unplugging the USB cable, uninstalling and re-installing the USB printer, etc.  If I were to plug the usb cable in with the computer and printer on, I /still/ get "The specified port is unknown" when XP is done with the install.  And, of course, no printer in Printer and Faxes.

So, I'm still stuck.  :(

RE: Cannot install USB printer, "The specified port is unknown"

Oh, I should also note that I used the 'cleanspl' XP power tool as recommended in this thread:

I'm sure I must've deleted something important with that tool.  Lesson learned I guess.

RE: Cannot install USB printer, "The specified port is unknown"

I am assuming that the printer is being connected directly to the computer.  You uninstall the printer, not the port. Does the printer manual tell you to install the software first and then the printer or to plug in the printer and then install the drivers.
To test the computers usb ability, can you install the other printer or another usb device.
Maybe you have a defective printer or cable.
What is the environment, is this an office? Do you have network printers.

RE: Cannot install USB printer, "The specified port is unknown"

The USB printer had already worked on this computer.  I had to uninstall the printer and run the cleanspl tool (as directed in the link above) to try to fix another problem.  Plugging the USB printer in is fine:  XP recognizes it is there, but there's no printer port for it to connect to (i.e.: LPT1, etc).  On every other computer here with a USB printer, in the Ports tab on the printer, it will list USB001 as a virtual printer port.   This does not exist on this user's computer.  I've tried other printers and cables.  The problem is inside Windows itself.

Looking at the registry (via regedit) I see that the USB Monitor is no longer in the registry (inside HKLM/SYSTEM/CurrentControlSet/Control/Print/Monitors).  I believe this was the thing I deleted by accident using the cleanspl.exe power tool.  I need /desparately/ to get that back in there.  I'm assuming that will fix the problem.

RE: Cannot install USB printer, "The specified port is unknown"

You could try manually re entering the info copied from another pc.
A simple fix may be to delete the root hub and then have XP discover it.
Most usb printer ports are not editable so I am not sure how you would do that.

RE: Cannot install USB printer, "The specified port is unknown"

Hi I'm Pablo from Argentina and i read this thread today because I have the same trouble.
Sorry, my English is too bad!!

RE: Cannot install USB printer, "The specified port is unknown"

I have already solved this problem.I had to replace the file windows\system32\usbmon.dll (it was damaged). I looked for the file of another PC with XP PRO to replace it, then I re-install usb-printer drivers and it work!!!
Thanks aroostook for open my mind when you wrote...(inside HKLM/SYSTEM/CurrentControlSet/Control/Print/Monitors)... in this location I found "usbmon.dll" and I thought...

Please if you try and resolve it...let me know

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members!


Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close