Windows update is a used by many IT Admin to keep the servers they manage to be updated with the latest patches so that it is compliant.
There could be times when the update failed to download for whatever reason and looking deeping into the issue can be done by going through the WindowsUpdate.log file located at C;\Windows.
For this instance, the update failed to download and you will see the error "0x80070005 occured while downloading update"
To resolve this issue, what is needed is just to stop the indexing service.
Once it id stopped, you can go ahead to attempt the Windows Update again.