The essence of my problem: I downloaded the installer, but when I run it, it shows error code 5 and stops the installation.
Do you have any other 3rd party AV software installed or not fully removed?
Try downloading Avast Premium again, in case of corruption of original file.
If the online installer fails, you could try the offline installer from the link here: New version 25.10
Note I am not an Avast Team member, just another user.
1 Like
First, Iām an Avast user and not an Avast Team member.
Common Causes for Error Code 5:
On a Windows computer, Error Code 5 points to a problem with permissions, such as a lack of administrator privileges.
Not sure if you are running as an Administrator of not.