Disable and Clear the cache
I have. Still the same thing.
I'm trying to duplicate/clone this site so I can run some tests and update the versions, but I've had no luck. This site is slowly going down hill and I'm trying to save it.
An other way to make sure that you are on the desired version of your site is to amend your local hosts file and add some rules like xx.xx.xx.xxhttp://www.mydomain.com.au to make sure you are browsing the site you are intend to.
And always remember to restart your browser after modifications.
My client's site is currently inaccessible, tripping 500 errors for every page. /login works but the dashboard won't come up.
Yesterday, quite by accident, I was able to get to the dashboard. Disabling cache restored the site to operation. Today I cleared the cache, then re-enabled. The site went dark again and I haven't been able to get back in.
It's running 5.4.1.
You can also manually delete the files inside the [root]/files/cache folder.
This sounds like your host might have updated your site to PHP version 5.4 which spits out lots of error messages. If you can get to your Dashboard->Environment, you should be able to check what PHP version you are on or check in your host's Control Panel.
Anyway, flipping the switch solved the problem.
PHP is at 5.3.27. The build looks new, in September, so maybe that was the problem. I was not involved until last week, so I don't really know the history.
I remain a bit confused by caching. The cache was full of stuff, but 48 hours ago I cleared it using the Dashboard. A lot of files and folders remained with dates earlier than the date I cleared it. So I've taken your advice and cleared it manually. I'll see what happens when I turn it back on.
I appreciate the good tips. Thank you.