We recently migrated from Exchange 2010 to Exchange 2013. We are at CU8.

I am noticing since the upgrade that not all of the Distribution groups listed in AD, nor any of the new users created recently in AD and then set up with a mailbox via the New / Existing User are being displayed in EAC under Recipients / Mailboxes.

If I do a search for their name in EAC, it returns the proper result and the account is there.   I can bring it up and edit settings, etc.   Same for the Universal Distribution groups.  But if I simply scroll down the list of either the mailboxes or groups in alphabetical order, they are not shown.

Does anyone have any idea what might be happening here?  Thanks.

How many users do you have?  Is it more than 500?  I believe the max the EAC shows is 500.  You should be able to see more if click the link below that says return All Results. 

Thank you, that did it.

I feel stupid for not seeing the Get All Results sooner, but thanks for pointing it out.

No problem. Glad to help.