Error during install:
[Microsoft SQL Server Native Client 11.0 SQL Server] There is already an object named 'sp_AttachmentGetid' in the database.
Receiving errors like this is a result of the user not being a database owner (administrator) on the Enterprise Alert database. The installation drops these procedures and adds them back again automatically. If the user does not have DROP rights they are not able to remove them thus when it tries to create the procedures during the install it already sees them and produces this error.
SOLUTION: Ensure the install is done by a user that has database owner rights on the Enterprise Alert database.