Login error: call to undefined function entity_load in User module I’m new to Drupal and I have a problem where no users can login (HTTP 500 and WSOD on POST of valid credentials, Drupal 7). The error message is:

“E_ERROR Error in file »user.module« at line 291: Call to undefined function entity_load()”

Any ideas on how to approach troubleshooting this?
Your error's stating that it can't find a function that should be in drupal core. Check you includes folder. There should be a file in there called common.inc, make sure the function entity_load is defined in there.