I have downloaded today the version of Avast Premier from Avast web. I have installed on a new HP laptop with no antivirus previously installed (so no Norton, McAffee, etc., only Windows Defender). Then uninstall, download, reinstall - the same problem. Looked at the file and it seems signed somehow. I can send it to kurtin@avast.com on Monday. Now I had to switch off secureboot temporarily in UEFI bios. The laptop OS contains some HP bundled software. Also after performing repair it writes that language pack is unavailable, but it is perhaps not connected.