Error 0x800720C1

Value: -2147016511 | 0x800720C1 | 2147950785

What does it mean ?

ERROR_DS_EXISTS_IN_MUST_HAVE  
Schema deletion failed: attribute is used in must-contain.
Value: 8385 | 0x20C1 | 0b0010000011000001

Where does it come from ?

FACILITY_WIN32  
Provides a way to handle error codes from functions in the Win32 API as an HRESULT. (Error codes in 16 - bit OLE that duplicated Win32 error codes have also been changed to FACILITY_WIN32)
Value: 7 | 0x007 | 0b00000111

Other Errors for FACILITY_WIN32