Have you tried:
– deactivating all plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s).
– switching to the default theme to rule out any theme-specific problems.
– resetting the plugins folder by FTP or PhpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems.
– re-uploading all files & folders – except the wp-content folder and wp-config.php & root .htaccess files – from a fresh download of WordPress. Make sure that you delete the old copies of files & folder before uploading the new ones.
I have a mirror site for test, where no plugin are active, just a couple deactivated, and the issue is the same.
What do you mean with default theme? I’m using Twenty Fourteen.
I’ll try resetting the plugins folder, but it is strange the issue has been generated in two different upgrades in two different web hosting services.
Sorry for having mislead you. I was trying to do something not available as a standard action. I have installed a plugin to do that.
