Showing results for 
Search instead for 
Did you mean: 

Invalid class string Source=msxml3.dll in Backup Exec Job History



I'm getting the following error on a 2008 R2 64 Bit system:

In Backup Exec 2010 and 2010 R2 opening the Backup Exec job history fails with the error One or more errors were encountered converting the job history into a web page for display in Backup Exec 2010

Invalid class string Source=msxml3.dll Description: Invalid Class String

I've tried the suggested fix listed in the following article: 

This doesn't seem to have worked for me so has anyone got any other suggested fixes to get the job history log working - other than strip out the Backup Exec install and start afresh?  I've got the latest BE updates installed.


14 Replies

Hi Try uninstalling Msxml 6.0


Try uninstalling Msxml 6.0 & if lower version of MSXML also present from program & features & then try doing repair of backupexec & see if that helps



Since you are on BE 2010 R2,

Since you are on BE 2010 R2, I would suggest that you upgrade to BE 2010 R3 which is the latest release. Your existing licence keys will work.  You can download BE 2010 R3 from either the fileconnect site or After your upgrade, do not forget to run LiveUpdate a couple of time to update it to SP1 and the latest hotfixes.

Hi, thanks for your

Hi, thanks for your suggestion.  I had a look to see if there were any Msxml components that could be removed but they're now included in 2008 server as a base component.  I did try running a repair of the Backup Exec install in case that would perhaps repair any corrupted file etc but it did not make any difference unfortunately.

We'll give this a go once

We'll give this a go once I've downloaded the installer so I will post an update next week.  Thanks for your assistance.

Downloaded and installed R3

Downloaded and installed R3 then proceeded to apply all the relevant patches using Live Update.  Jobs are working fine but still get the error when opening the job history. 

Like the previous TechNote

Like the previous TechNote suggested this may be an issue with certain dynamic linking libraries (DLL's) not being properly registered with the system.  You could try the following to see if it resolves your issue.


Create a batch file (.bat) or command file(.cmd) in notepad and post the following into it :


net stop wuauserv

regsvr32 wuapi.dll

regsvr32 wups.dll

regsvr32 wuaueng.dll

regsvr32 wucltui.dll

regsvr32 wuweb.dll

regsvr32 jscript.dll

regsvr32 atl.dll

regsvr32 softpub.dll

regsvr32 msxml3.dll

net start wuauserv

Save it on your Backup Exec Media Server and run from the CMD Shell (Prompt).

Thanks for the suggestion

Thanks for the suggestion Joshua.  This is a 64 bit implementation of Windows so do we need to ensure we run the regsvr32 executable in the SysWOW64 directory?

regsvr32 should be avaliable

regsvr32 should be avaliable to run from any directory on your server.  as long as your system path includes the windows install directory it should run.

Ok the plot thickens.  I ran

Ok the plot thickens.  I ran command prompt as administrator, browsed to the bat file and ran it.  There are three dll's that it cannot register: wucltui.dll and wuweb.dll failed to load.  Jscript.dll loaded but the call to DllRegisterServer failed with error 0x80004005. 

Have you tried running sfc

Have you tried running sfc checked to repair these files ?

WCLTUI.DLL is the Windows

WCLTUI.DLL is the Windows Update Client UI Plugin

WUWEB.DLLis the Windows Update Web Control

JSCRIPT.DLL  is a function which gives extra functionality for Microsoft JavaScript

Do you have Windows Update installed and enabled on your system, as well as Java?


No we don't have Java

No we don't have Java installed as I don't believe there has been a need to install it as yet on this particular server. The server receives it's Windows updates from a WSUS server on the domain rather than having automatic updates set and pulling them down from the internet.  I can verify that the device is listed on our WSUS server and has installed updates that we have approved.

If that is the case, has

If that is the case, has there been a behavior change with the other files now registered?

No unfortunately the

No unfortunately the behaviour is the same with the job history not being displayed.