Disabling AD account removes email address

I am currently rolling out Sophos Central Email Security and came up with the same question. Disabled users are not present as valid mailbox thus letting my resource mailboxes (w/ disabled user accounts in AD) not receiving email. I could not find an option within ADSync either.

Whats the best practice?

Mark Sime said:

Hello. 

When a user leaves my firm, our procedure is to disable the AD account, but on doing the this, after Sophos Central syncs (AD Sync Utility), the users email address is removed from Central and prevents emails being delivered to the mailbox. We require a users mailbox to remain active for some time after they have left.

Ive looked at the sync tool options, and dont see anything in there to address this. 

 

Any idea's ?