Why can't I uninstall a module if I deleted a field type in a content type? I have an installation of Drupal 7. I installed Field Collection module. I created a content type (Books), added a collection type field, and created a View showing these data. Now, I deleted the collection type field in Books, and now I am not able to uninstall the module. I have run cron and cache delete to no avail. The message displayed in the modules page is the following.

Field collection  


  7.x-1.0-beta11+13-dev
  Provides a field collection field, to which any number of fields can be attached.
  Requires: Entity API (enabled)
  Required by: Drupal (Fields pending deletion)
You can try this process
Log into database and -&gt;
Select * from field_config where type = &quot;field_collection&quot;

Delete the rows
Same with field config instance table like
SELECT * FROM field_config_instance where entity_type = &quot;field_collection&quot;;

Delete the rows
You can also check.

1.) first remove all the fields inside the Fields Collection.
2.) Then remove the field collection from the content type
3.) Run the Cron
4.) try to disable the module, if you cannot then Go ahead with first query statements above.

Get more details Here.