I’m having the exact same problem on Win 7 x64 now. Followed the steps exactly, didn’t work.
Trying to install v8, not sure how to find exact version now as it was downloaded a few days ago.
History: downloaded, unplugged network cable, uninstalled old version, rebooted. Installed new version, install ran fine, got Access denied error. Googled, found out about blocked files in Win7, discovered setup file was blocked. Uninstalled, rebooted again, unblocked setup file, installed. Same Access denied.
Interestingly, if you right-click the shortcut on desktop (icon is a generic icon, Avast icon fails to load for AvastUI), then properties, then try to open Compatibility tab, it gives Target not valid error: “the name “C:.…\AvastUI.exe” specified in the target box is not valid. make sure the path and file name are correct” even though I used default (even express) install settings.
Any help appreciated.
PS previously, AVG was installed by the IT shop. We brought it into the work environment where Avast is used. AVG was uninstalled, but not completely removed using a removal tool, before attempting to install Avast the first few times. Latest time, we used the AVG removal tool as well, still failed.
PPS Avast works in Safe Mode and Safe Mode with Networking.
PPPS for one of the installations, I changed the owner of the Avast folder in Program Files (right-click, Properties, Security, Edit, Change Owner or something), to see if it wuold help. It helped the administrator, but if it went to a user’s account (which it successfully did only once), it did not help.