The following script will interrogate the orphaned users in each database on a particular server. All records from sysusers where the record contains a SID are selected, before using suser_sname(SID), which returns the login name associated with a security identification number (SID). If the returned value is null, the database user is not attached to a valid login.
Various filters are subsequently applied to exclude rows not required eg database and application roles.
A temporary table is then populated with data from each database using the sp_MSforeachdb procedure.