If you have the perpetual prompt from Vaio Update that it needs to update itself, the fix is to disable SmartScreeen under Windows 8.
By deafult Windows 8 will block applications that Microsoft deem are not popular enough, but as Vaio Update is trying to install silently, the block is also silent.
To disable smartscreen
- press Start
- type "smartscreen"
- click "settings" on the right
- click "Change SmartScreen Settings"
- Change the smartscreen settings to "Don't do anything"
You can now run the update for VU and it will complete, ask for a restart and then start picking up new updates.
You may want to re-enable SmartScreen once your Vaio updates are complete, but you will have to disable it each time you want to run Vaio updates until Sony's servers are approved by MS to bypass SmartScreen checks.
