Thanks Marcos and itman for your responses --
Yes, my Network / Firewall setting is on Interactive mode, where both options are checked [these are the default settings]: 'enable detection of application modifications' and 'allow modification of signed (trusted) applications'
[in: ESET Smart Security8>enter Advanced setup>open Network tree>open Personal firewall tree>Application modification detection]
In the same window, you are able to add paths to application files to exclude from detection, or filtering; I had excluded the Picassa updater [another Google product], and another for Canopy, a Python package manager. I manually added GoogleUdate.exe to the exclusion list to see if that would eliminate the application modification warning but it did not.
I have had my firewall set up in interactive mode for several years - I installed Chrome on this machine about 1.5 yrs ago but this is the first time I have received this warning on Chrome's GoogleUpdate.exe -- so to be safe and to test I uninstalled/reinstalled Chrome, while retaining the same settings for ESET. With GoogleUpdate.exe still in the exclusion list for application modification warnings, I received no warning on Chrome's fresh reinstall after clicking 'about' in Chrome. I then removed GoogleUpdate.exe from the exclusion list in ESET and after checking for updates in Chrome again got the same application modification warning on a certainly clean Google updater file. I 'allowed' this file thru the ESET GUI [which adds the path to the exclusion list] and now Chrome updates as expected with no warnings from ESET.
So I will mark this issue as 'solved' -- since I was able to reproduce the warning on a clean copy of Google's updater, it seems safe to keep in the exclusion list, essentially I guess making firewall filtering automatic instead of interactive for those application files. Though I still don't understand what changed to create this issue.
