field_type with existing data cannot have its keys changed our site is throwing up the following error:

A list field (field_type) with existing data cannot have its keys changed. in list_field_update_forbid() (line 363 of /modules/field/modules/list/list.module).


I've already researched and found on the drupal developer site a documentation about this error: https://drupal.org/node/1294264 

But honestly I don't know what to do. 

Has anybody an idea?

Thank you and best wishes

Chris
Try to delete the specified config file:

drush config-delete &lt;name of the config to delete&gt;

and than import the config again:

drush cim