I was using a List category posts plugin and while editing for custom need a one file of this plugin - i have got an error (it was because of wrong usage of backslashes to escape special characters within quotes):
Parse error: syntax error, unexpected T_STRING in /home/i/ingeniumru/visionlabs/public_html/wp-content/plugins/list-category-posts/include/lcp-catlistdisplayer.php on line 487
And this error on all pages through the site (admin panel also), which even don't use the plugin functionality.
I ask the community to explain such a correlation between Wordpress php-files.
WordPress load all active plugin and the active theme (just to know if he should use it or not).
If you have a plugin that make your website down, including backend, you can just go to your FTP (zip it : to have a backup) and remove the plugin folder. Then your site will be ok again.