During the database upgrade process on database '%1!s!', a user object '%2!s!' named '%3!s!' was found to already exist. ...

During the database upgrade process on database '%1!s!', a user object '%2!s!' named '%3!s!' was found to already exist. That object is now reserved by the system in this version of SQL Server. Because it already exists in the database, the upgrade process is unable to install the object. Remove or rename the user object from the original (pre-upgraded) database on an older version of SQL Server and then retry the database upgrade process by using CREATE DATABASE FOR ATTACH. Functionality that relies on the reserved object may not function correctly if you continue to use the database in the current state.