SAVXP update failing

Hello, 

I'm getting the following message in my update log each time I try to update:

Installation of product SAVXP failed because of an unexpected error

When I look in the install log, I'm seeing:

2018-06-27 07:09:37 Info: Detected version of SAV has major version number: 10
2018-06-27 07:09:37 Unable to QI IProductConfig
2018-06-27 07:09:37 Info: productType: 0
2018-06-27 07:09:37 PROCESSOR_ARCHITECTURE environment variable is: AMD64
2018-06-27 07:09:37 Info: Logging started: installing/upgrading Sophos Anti-Virus
2018-06-27 07:09:37 Info: InstallFromPath is: C:\ProgramData\Sophos\AutoUpdate\cache\sophos_autoupdate1.dir\decode\savxp\
2018-06-27 07:09:37 Info: InstallToPath is:
2018-06-27 07:09:37 Info: Detected version of SAV has major version number: 10
2018-06-27 07:09:37 Info: Detected version of SAV has minor version number: 8
2018-06-27 07:09:37 Info: registryInstallTo [overriding InstallToPath] is: C:\Program Files (x86)\Sophos\Sophos Anti-Virus\
2018-06-27 07:09:37 Checking for problem versions of SAVI - Install path:C:\Program Files (x86)\Sophos\Sophos Anti-Virus\
2018-06-27 07:09:37 Veex.dll version '3.72.1.2411'
2018-06-27 07:09:37 INFO: Checking the validity of the VDL manifest file.
2018-06-27 07:09:37 ERROR: A file listed in the manifest did not match the file found at the target directory.
2018-06-27 07:09:37 ERROR: Failed to validate the VDL data manifest file.

Windows 7 PC, patched up to date. Endpoint software has been installed for years and no recent changes. Any ideas what I can do to resolve this? I recently had to restore the system to a restore point so that may have confused something?

Thanks for any help.