The Administrator is unable to remove a record type (MCO, for example) because it is being used by the Chatter User Profile.
The default Record Type needs to be removed from the Chatter Profile. This cannot be done through the UI.
Please review the two methods below:
Method 1: Contact Veeva Support.
Veeva Support works with Salesforce.com (SFDC) to change the default Record Type for the Chatter User Profile, which allows the ability to remove the record type.
Method 2: Manually remove the Record Type.
Remove the Record Type using this sample link:
- Instance is the SFDC server the org is running on
The Object is the name or ID of the object (Contact, Account or the ID of the custom object)
The ProfileID is the ID of the profile (Chatter Free User or Chatter Moderator User as examples)
Vault Help Documentation: Deleting Default Record Type