Deleting a Custom Record Throws an Error: "This custom record cannot be deleted because it is referred to by custom fields".

User is unable to delete a custom record type even when it is not referred to by any workflow/script, item, entity, or transaction fields.

Steps to Reproduce:

1.    Navigate to Customization > Lists, Records, & Fields > Record Types.

2.    Click on the Custom Record Type's name.

3.    Navigate to More Actions > Delete.

Actual Result: This custom record cannot be deleted because it is referred to by custom fields.

Expected Result: Delete the custom record type

To resolve this, remove all sublists for that record type:

1.    Navigate to Customization > Lists, Records, & Fields > Record Types.

2.    Click on the Custom Record Type's Name.

3.    Navigate to Sublists subtab.

4.    Remove all sublists.

5.    Navigate to More Actions > Delete.

Another solution is to delete the Saved Search related to the custom record type:

1. Navigate to Lists > Search > Saved Searches 
2. Filter the list by Type = <Custom Record Type>
3. Edit the Saved Searches
4. More Actions > Delete