Sadly, this didn’t work for me. While I DID have a plugin that was switching contexts based on url, I went to the extent of
- uninstalling all packages
- re-uploading
- disabling then *deleting* all my plugins manually (having backups of course)
- manually emptying the cache
- restarting the browser and liberally emptying browser caches
- asking it very, very nicely by means of an uploaded photo of a box of chocolates
...yet I still I’m greated with an "Access denied" on the document tree and most other parts of the Manager. I don’t even have permission to logout from the manager.
Is there anything other than packages, the cache, or plugins that could be causing my woes?

(Thanks!)