Backup Exec installation fails with error 1603 on SQL Express if MSXML 6 Service Pack 2 (KB954459) is already installed.

  • Article ID:100007402
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  • Product(s):Backup Exec


Backup Exec installation fails if MSXML 6 Service Pack 2 (KB954459) is already installed. The Backup Exec install log will show a 1603 error.

If you try to install SQL manually you will see an error when SQL Express tries to install MSXML6. See Figure 1 & 2 below: 

Error Message

Figure 1


You may also get the following error dialog:

Figure 2


 Installation of MSXML 6.0 Parser (KB933579) failed because a higher version already exists on the machine. To proceed, uninstall the higher version and then run MSXML 6.0 Parser (KB933579) Setup again.

This SQL/MSXML install issue is documented in the following article:


The solution is to uninstall KB954459 prior to installing Backup Exec - or more specifically prior to installing SQL Server 2005 Express Edition.

However, in most cases trying to uninstall KB954459 via Add/Remove programs will fail. The resolution is to manually remove KB954459 from the Windows Installer database.

This can be done manually on each machine as described in KB968749 or it can be done by calling MsiZap.exe from a command line and passing in the product code for KB954459 which is {1A528690-6A2D-4BC5-B143-8C4AE8D19D96}.

The Msizap command line to remove MSXML6 SP2 KB954459:

"<PATH>\MsiZap.exe" T! {1A528690-6A2D-4BC5-B143-8C4AE8D19D96}

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