Tech's suggestion also has the great benefit of removing the avast update from trying to compete with every other startup program that insists that its updates are the most important thing in the system.
This is especially true during Windows update week. Windows automatic updates seem to hog resources even to just determine that updates do exist but you are just not allowed to download them yet (to prevent overload of Microsoft's servers). So this is happening at every startup during the Windows update period until you have been permitted to download the updates. Although I do not have "smoking gun" logs to prove it (a bit hard to get on an overloaded system at startup) I am reasonably certain that the Windows automatic update process, at this time, can prevent the avast automatic VPS update from getting timely access to it servers and causing avast to report an automatic update error - especially on older, less powerful systems. This past week was Windows update week, some folks this week waited 4 or 5 days before being permitted to download the Windows updates through the automatic update process.