I am installing the software as an administrator and have UAC turned off. The file permissions on AIDA64.exe have not been modified from the defaults and upon checking, grant both local Administrators and SYSTEM 'Full Control' permissions. Based on that, I don't think the installer's failure to replace this file is due to permissions.
Since I have AIDA64 v5.99.4900 installed via the installer, it seems like a bad idea to download the v6.00.5100 portable and extract those files into the currently installed folder. Although the AIDA64.exe will be replaced, I'll be left with Windows reflecting v5.99 is installed but the folder contains files of the newer v6.00. I do want this issue resolved but as I mentioned, I also want to ensure I am able to update to future releases.
I would love to "dig down deeper" to find out why the update process is failing. Unfortunately, after the error message, the installer rolls all of the changes back. Is there a log of the installer's activities I can reference?