About 2 weeks,or so, ago I started getting error messages - the update program runs for about 5 to 7s stops and says it is unable to update. your help please. I’ve tried changing settings, manually update etc HELP

What happens if you try a manual virus definitions update from the avastUI ?

If that also results in an error, please post the full text of the error and try this:
What is your operating system and firewall ?
Does it allow avast.setup internet access ?

  • If it does delete the entry for it and do a manual update, this should force the firewall to ask permission again.