I installed the free WordFence security plugin on my site and was immediately unable to login as admin. No message was received and I was presented with a white screen. Tried typing various direct urls to sections of my site but same white screen problem. Cleared browser cache and tried using other browsers but no luck.
I then logged in as a user with editor permissions and had no problems accessing my site with the expected editor level access restrictions.
I logged out and used the following address format to access my site again-
I logged in as the same user with editor level access and immediately got full admin access to my site. This was fortunate for me as I was able to uninstall this plugin and now all is well.
If you have this plugin installed, it might be worth checking that this is NOT POSSIBLE on your site.
Just thought you should know.