VPSUPD is a file downloaded then run to update the Avast virus defs in lieu of doing it online.
vpsupd hasn;t worked since Avast24.10. Why does Avast create this file if it doesn’t work.?
I use it on Avast24.9. I have multiple builds with Avast24.9, so using vpsupd is faster and better than an online update. My internet is sometimes iffy, and an online update sometimes fails.
When you download vpsupd, at the end an error check is done automatically to ensure it is intact.