All the Joomla sites I monitor are on the same host, and on that host, the right answer for Forward symlinks is "Yes", so it should be "Yes" for this site too. But as soon as deleted htaccess, got back in and set Follow sym to "No", I could work the back end.
Also unique to this site, the other sites are ALL Joomla. This one is only Joomla in one directory and for maybe 6 pages with a couple dozen images.
Nonetheless, its backup file is 100 MB (55 MB for a full backup on a huge site). This makes me wonder if I have set the site/domain (System Configuration) correctly in htaccess. For HTTPS and HTTP, should I put site.com or site.com/sub-directory?
For base directory of the site, do I put / or do I put /sub-directory (where Joomla is installed)?
Lastly, right now, in Chrome and in Safari, no problems when I go to the main screen of Admin Tools. I see all icons and images.
In Mozilla Firefox, right now, the back-end freezes (I cannot click an icon, select a menu, or log out). On the other machine, I had Firefox open, in Admin. Tools and so I can click the icons but cannot get the back-end menus.
Also, the only icon that loads is the green tick for latest version of Admin Tools. All other graphics do not load.
I am out of ideas here!