Windows Vista – Windows Update Stopped Working In September 2016
If your Windows Vista has stopped updating then this could be the fix you need.
The update agent can’t handle update KB3168965. You need to download and install this one manually.
More information – http://support.microsoft.com/kb/3168965
Set automatic updates to “Never check for updates” then reboot and then install this update and then restart Windows.
KB3168965 update 32bit-
KB3168965 update 64bit-
Once you have done all this, you will need to reboot and then re enable updates and this should then be ok.
We have seen this issue 2 times now, and we have known of other company’s that have encountered this same error on Windows Vista so it must be quite common.