O365 SharePoint - Duplicate Content Type

Scenario

• You try to create a new sub-site from a template or try to create a new content type
• Office 365 SharePoint Online (SPO) environment

Issue

• Internal SharePoint validation identifies a duplicate Content Type
• Typically this is due to a migration of content types or a failed feature activation/deactivation
• Ex: "A duplicate content type name "Document Set" was found.
• You cannot remove the duplicate Content Types because they are part of a feature or in-use

Resolution

• Rename the duplicate Content Types using the Site Settings/Content Types interface

• _hidden content types (like "System Media Collection") require using PNP PowerShell cmdlets to get the ID to pass into the browser URL

  $smc = Get-PnPContentType "System Media Collection"
  $smc.Id
  StringValue                                  TypeId
  -----------                                  ------
  0x0120D50067B20E13E9C3AA458AEF3A8392B641FD01 {da0f1e90-296f-480e-bc27-cefe51eff241}

• Edit another content type and then replace the ctype query string parameter to edit the _hidden content type
• Replace the following from the Document Set Edit Name Page
  /_layouts/15/ctypedit.aspx?ctype=0x0120D50067B20E13E9C3AA458AEF3A8392B641FD