CANNOT ACCESS ADMINISTRATOR PAGE

That can be caused by invalid database connection but as I understand fronted works so that is not case. Install host start on localhost and compere /administrator folder if some strange new file appeared.

1. the front end is what went down first, and in some way (an unexpected string in a .php file?) interfered with the database tables/fields, defaulting to the lengthy error message in the Content area of the template (what I call the "pink error" .

2. I have not yet set up a localhost environment, but I'll try to work that in to my routine ... in the meantime, I'll be using Akeeba Admin Tool Pro's feature that watches for changes to any/all such files.

3. On this last point, I captured one difference between the mysql.php (mentioned in the error_log) freshly unzipped and the one that existed in the installation at the time of crash: lines 55-60 of the original are missing in the installed file (screenshot attached). Is this 'as expected'?

Thanks!

try to install some anti-virus for joomla or ask your hosting provider to do scan. If files are altered that can mean there is virus in your site.

Still waiting for a response from my host ... my current VPS isn't on the server that provides end user (i.e., me) access to run scans. I have run my own virus/malware checks on the backups I have (off the server), and all of these are clean.

I have no idea what it might be. Maybe just some component creates problem or something like that.

Yes, it is a strange occurrence. Also did a complete backup of my entire hosting account and scanned that = clean.

So, I've got my notes and if something else happens that sheds light on this I'll post again ... technology shall not rule us!

Thanks, Ivan