The private mailbox database design gives the server considerable advantages in efficiency, scalability, and administratability.

This was very advanced for its day, but had major scalability issues and Carnegie Mellon wanted to move to a standards-compliant mail system that met or exceeded the feature set of AMS.

In 1994 the Computing Services Division at Carnegie Mellon addressed these goals by starting the Cyrus Project.

The Computing Services Division later developed Cyrus "Murder" clustering,[a] and after several revisions deployed it within Carnegie Mellon in the summer of 2002.

[5] In the fall of 2016 Carnegie Mellon announced the retirement of Cyrus IMAP as their electronic mail storage service, with Cyrus users required to choose between on-campus Microsoft Exchange and Google "G Suite" off-campus mail.