Certain Profiles like the Chatter Free User can be assigned Record Types which cannot be removed by clicking an edit link in the Record Type Section of the Profile. This prevents Record Types from being deleted. In order to remove the record type from the Profile a URL 'Hack' must be performed.
Please refer the link for url hack.
https://success.salesforce.com/answers?id=90630000000h2pXAAQ
Added below the content from the above link to ensure completenedd of the answer:
Certain Profiles like the Chatter Free User can be assigned Record Types which cannot be removed by clicking an edit link in the Record Type Section of the Profile. This prevents Record Types from being deleted. In order to remove the record type from the Profile a URL 'Hack' must be performed.
First, the Enable Enhanced Profile User Interface checkbox in the User Interface must be deselected:
Setup> Customize> User Interface> Setup Section> Deselect Enable Enhanced Profile User Interface> Save
Proceed with the following Steps:
1)Please follow this click path:
Setup> Manage Users> Profiles> System Administrator> Navigate to Record Types> Click the Edit Link on the Object in question's Section
At this Point you will be at the Edit Record Type Settings Page for the Object.
2)Copy the URL from the adress bar on your browser and paste it into note pad:
https://naX.salesforce.com/setup/ui/profilerecordtypeedit.jsp?id=xxxxxxxxxxxxxxx&tid=Opportunity&pn=System+Administrator&retURL=/xxxxxxxxxxxxxxx
3)Now follow this click path
Setup> Manage Users> Profiles> Chatter Free User
4)Copy the 15 digit Salesforce Id from the URL in the Adress bar of your Browser:
yyyyyyyyyyyyyyy
5)You are now going to replace the id in the Edit Record Type Settings Opportunity Page ( the first id number right after the "jsp?id=" in the URL ) with the Id from the Chatter Free User.
This:
https://naX.salesforce.com/setup/ui/profilerecordtypeedit.jsp?id=xxxxxxxxxxxxxxx&tid=Opportunity&pn=System+Administrator&retURL=/xxxxxxxxxxxxxxx
Should now look like this:
https://na5.salesforce.com/setup/ui/profilerecordtypeedit.jsp?id=yyyyyyyyyyyyyyy&tid=Opportunity&pn=System+Administrator&retURL=/xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx was replaced with yyyyyyyyyyyyyyy
6)Now take the modified Url and place it in the Adress bar of your browser and hit enter.
*************This will seem to have taken you to the System Administrator's edit page but you are in the right place.******************
7)You will now be able to remove the value by highlighting it and selecting remove. Switch the Default record type to whatever you like and hit save.
All you need to do now is repeat this for any other Profiles in which it is necessary, then Deactivate and Delete the Record Type.
Best Answer
Standard Profiles come default with set User Permissions. User Profiles and their customizations are set based on the org type:
Essentially, these profiles are set up and only some of them allow certain functionality. Not all of the profiles allow access to certain objects (specifically, profiles associated to Portals are very restrictive). This is just how the profiles are set up.