If you face these error ” Coding error detected, it must be fixed by a programmer: Failed to unserialise data from file. Either failed to read, or failed to write. ” in moodle here is the solution

First login to your moodle server and navigate to moodle directory

cd /var/www/html/moodle then execute following command php admin/cli/purge_cache.php

if some times give the same error “Coding error detected, it must be fixed by a programmer: Failed to unserialise data from file. Either failed to read, or failed to write. ”

if so then navigate to moodle data directory /var/www/html/moodledata/cache and then delete the cachestore_file but do not delete the core_component.php file

rm -rf cachestore_file

Then restart apache using systemctl restart httpd command

Then goto your moodle domain again.if error still is there execute this

yourdomainname/admin/purgecaches.php then navigate to your moodle domain now everything working perfectly