WordPress 4.6 crashed my site
Fatal error: Cannot redeclare the_post_thumbnail_caption() (previously declared in ….
This error occurs because the_post_thumbnail_caption is a new function in WordPress 4.6. However, people have been using this function for over 5 years now. How? Stackoverflow and other WordPress forums are flooded with questions asking how they can print out the thumbnail caption. Since this wasn’t a built-in function before, the answer was to make your own function which was appropriately named the_post_thumbnail_caption.
Many theme authors, myself included, are now guilty of simply copy-pasting this function without adding their own theme prefix. To avoid errors like this, functions within a theme should be prefixed with something unique to the theme like “mymonkeytheme_the_post_thumbnail_caption”.
If you have this error, contact your theme author and ask them to fix the theme.