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Error 1721 or 1722 during Libronix installation


When reinstalling Libronix it is halted by the following error:

Error 1721 (or Error 1722). There is a problem with this Windows Installer package.

This error is occasionally caused by an incomplete removal of Libronix, but usually caused by a problem with Microsoft's XML Parser 4. If Libronix was installed, partially or fully, prior to receiving the error, follow steps under Solution 2. If this is the first attempt at installing Libronix, follow steps under Solution 1.


Solution 1:

The Microsoft XML Parser may need to be reregistered or reinstalled.

Make sure that your user account has administrative rights on the computer. If it doesn't, please contact your IT department or the person who set up your computer.


To register the XML Parser in XP:

  • Click on Start | Run.
  • Type or copy and paste the line below, then click OK:
  • regsvr32 msxml4.dll
  • A message should pop up saying "DllRegisterServer in msxml4.dll succeeded." Click OK.
  • Repeat the Libronix installation. (Restart computer first for Windows 98/ME.)


To register the XML Parser in Vista or Windows 7:

  • Click on Start button and click into the Start Search box (click on image below).

  • Type cmd.exe. When cmd.exe (or cmd) appears at the top of the Start Menu under Programs,
    right-click on the filename and choose Run as administrator.
    • If a User Account Control (UAC) window appears asking for permission, click Continue.
    • A command prompt window will open (click on image below).

  • Type: regsvr32 msxml4.dll and press Enter. (For Vista & Windows 7: 64-bit, type: regsvr32  "C:\Windows\SysWOW64\msxml4.dll" and press Enter).
  • A message should pop up saying "DllRegisterServer in msxml4.dll succeeded." Click OK.
  • Type Exit at the prompt and press Enter to close the command window. 
  • Repeat the Libronix installation.

If the above command does not succeed, try reinstalling the Microsoft XML 4 parser:

  • Click the following link to install the Microsoft XML Core Services Service Pack 2: MSXML4SP2.msi
  • Click on Run (or Open). Follow the steps in the Setup Wizard, selecting Install Now in the final window. Click Finish when complete.
  • Repeat the Libronix installation.


Solution 2

If the 1721 or 1722 error occurs when reinstalling Libronix, open My Computer and navigate to C:\Program Files\Libronix DLS. Delete the CommonInbound, and System folders (leave Resources). Try the installation again. If the error reoccurs, click on the following link for instructions on uninstalling and reinstalling the software: Using the Windows Installer Cleanup Utility to uninstall Libronix.