Exchange 2016 - Email data automatically gets Deleted

When you say their mailbox data gets deleted, do you mean out of AD, the mailbox itself is removed or the content of the mailbox?

Thanks

Alex

Check the "keep deleted items retention" days i.e. default 14 days on the mailbox database properties in EAC.

If it is zero then it might purge all items instead of moving them to deleted items.

Have you enabled audit logging?

https://docs.microsoft.com/en-us/exchange/policy-and-compliance/mailbox-audit-logging/mailbox-audit-logging?view=exchserver-2019

Alex - It's just some of the email data in their mailbox, not the mailbox itself or AD data.

Saif - The retention time is set the default database setting of 14 days, All users have the same setting, But some users data is getting deleted.

 I'm currently checking Junk E-mail Filter settings, 3rd party Virus scanners, 'Ignore Conversation' in Outlook, and seeing if these users are using any smartphones or tablets

Jason - Audit logging is disabled for all user mailboxes at this time.

The best way to narrow down whatever mechanism is responsible going forward is to enable audit logging. 

sounds good. Thanks Jason!

have seen this happen sometimes when using a mobile to sync emails. If the affected mailboxes have mobiles syncing email , check the settings in whatever mail app they are using for settings to do with deleting emails or try remove the mail sync and see if the problem goes away

Daryl - good call you're right especially with 3rd party email apps or Apple Mail.  This was especially bad back in the Blackberry days.

Your help was truly appreciated!!