Any help on this much appreciated.
We have a hybrid environment with an on-premise Exchange 2013 server. It's been noticed that the mail tips for one of our mail-enabled security groups was incorrect. After checking the membership, I found the MSExchGroupMemberCount attribute wasn't updating. It's showing 798, when the true figure was 559.
So I manually updated it to reflect the true number, however that did not resolve the problem.
I then looked to the server, and discovered in the ChangedGroups text file that the server was not processing all of our mail-enabled security groups.
I'm not entirely sure how this has occurred or how to start resolving this. I'm guessing it may have something to do with the arbitration mailbox, but have no idea. The server used to be part of a DAG of 2 servers, but this has long been removed.
Andrew.
Andrew France - http://andrewsprivatecloud.wordpress.com