Why does auto-archiving turn itself on?

[bibi_28-]

Auto-archiving turns itself on everyday and this deletes messages from my shared mailbox.

Auto-archiving is not enabled for my shared mailbox.

[#2]

And by auto-archiving you mean the client-side functionality? Or retention policies?

[#3]

Client Side

[#4]

Have you checked if there are any outlook rules set up in your client??