Error: "XML returned from Engine was invalid" when performing a database restore/backup. (4238610)

Error received after upgrading LiteSpeed and performing a database restore/backup:

"XML returned from Engine was invalid"

This error message is common when an upgrade has not been successfully carried out. There is a mismatch of program DLL files and/or stored procedures used by LiteSpeed.

1. Uninstall LiteSpeed using the Add/Remove Programs applet in Control Panel.
2. Reinstall LiteSpeed.
3. Execute the following SQL command in Query Analyzer against the master database to ensure that both the Product Version and Engine Version are the same:

EXEC xp_sqllitespeed_version

If the Product and Engine versions displays in the output are the same, you should no longer receive the error message.
If the versions are not the same, it is most likely that the uninstall was not able to clear all the files. Follow the steps below to perform a manual uninstall to remove the older version of LiteSpeed from the computer:

1. Run Add/Remove Programs from Control Panel.
2. Delete Folder C:\Program Files\DBAssociates\ or C:\Program Files\Imceda\.
3. Backup and Delete the Registry Keys
HKEY_LOCAL_MACHINE\Software\DBAssociates\ or HKEY_LOCAL_MACHINE\Software\Imceda\
HKEY_CURRENT_USER\Software\DBAssociates\ or HKEY_CURRENT_USER\Software\Imceda\

4. In SQL Server Enterprise Manager | Master database | Extended Stored Procedures, drop the following:
xp_backup_database
xp_backup_log
xp_file_search
xp_memory_size
xp_objectrecovery_viewcontents
xp_objectrecovery
xp_restore_database
xp_restore_log
xp_restore_filelistonly
xp_restore_headeronly
xp_restore_verifyonly
xp_restore_checkpassword
xp_restore_setinfo
xp_sqllitespeed_licenseinfo
xp_sqllitespeed_version
xp_view_tsmcontents

5. Delete, or rename these files, written to the Microsoft Binn directory:
xpSLS.dll
xpLogShipping.dll
xpSLSImportStats.dll
slssqlmaint.exe

When removing xpSLS.dll from the directory C:\Program Files\Microsoft SQL Server\MSSQL\Binn, you may get an error saying this file cannot be deleted because it is in use, you can simply rename this file to something like 'xpSLS.dll1'. The next time this server is restarted, you will be able to successfully delete this file.