This Error Message Article explains the Microsoft SQL Server Management Studio error message “Specified cast is not valid. (SqlManagerUI)” and details how to fix the underlying problem that caused it to appear.
This message appeared when a client tried to restore a SQL backup file made from another instance of SQL using a newer version.
SQL is generally not backwards compatible. The original back up file must be recreated in the same version of SQL that will restore it.
Error First Appeared: Windows 7 running Microsoft SQL Management Studio 2008R2