I installed Algolia search on a staging version of my website and it worked wonderfully (after a bit of tweaking). I've just tried to apply that to my production install, starting by installing the extension.
Unfortunately, when I do it it breaks search and breaks the admin console (search 500s and admin console puts up the "exception" screen). It seems this is because the Algolia install didn't install all files. E.g. (from exception.log):
exception 'Mage_Core_Exception' with message 'Invalid block type: Algolia_Algoliasearch_Block_Adminhtml_Notifications' in /home/cluster-sites/5/y/yateley10kseries.kallisti.co.uk/public_html/app/Mage.php:595
2018-07-04T12:55:47+00:00 ERR (3): Warning: include(/home/cluster-sites/5/y/yateley10kseries.kallisti.co.uk/public_html/includes/src/Algolia_Algoliasearch_Model_Observer.php): failed to open stream: No such file or directory in /home/cluster-sites/5/y/yateley10kseries.kallisti.co.uk/public_html/includes/src/Varien_Autoload.php on line 94
OK - so it's obvious the problem - incomplete install - but the little green Magento Connect install screen said it went fine...? Is there a log of that somewhere I could use to debug?