Seaquel
SQL Server error code

SQL Server error 1925

SQL Server raises error 1925 at severity 16, which marks a problem with the query or data that you can correct.

Cannot convert a clustered index to a nonclustered index by using the DROP_EXISTING option. To change the index type from clustered to nonclustered, delete the clustered index, and then create a nonclustered index by using two separate statements.
Msg1925
Severity16
Group1000–1999

Source: Database Engine events and errors