Rolling back from Exchange 2019
Hello everyone - bit of a long shot, but hoping someone can advise. TL;DR: Is it possible to introduce a Exchange 2016 in a 2013/2019 co-existence and move everything to that to bin off a troublesome Exchange 2019 box? We have a client who were running Exchange 2013. A new Exchange 2019 has been spun up and installed with CU 7. Everything has been migrated over to the new server - DNS, Public folders, mailboxes etc - and from a migration point of view, there were no errors or anything unusual at the any of the migration stages. However, since we've moved the mailboxes over, we've seen a high number of errors on the Exchange 2019 server as well as poor user experience with users running Outlook 2016. The most visible of these issues is the Microsoft Exchange RPC Client Access service terminating unexpectedly at random times - some days it will do it 6 or 7 times, other days not at all. This drops connection for users running Exchange, and in some causes causes a crash. Users are also reporting that Outlook is pretty sluggish and prone to crashes. Users never had this kind of degraded performance when on the Exchange 2013 box. We discovered that MAPI over HTTP was never enabled on the Exchange 2013 server, so looked to change some mailboxes to use MAPI over HTTP as a test, but performance is even worse with this than RPC of HTTP. Users typically access Outlook on a terminal server with cache mode disabled - we're looking at enabling cache mode and see if this improves performance, but to be honest at this point with so many niggly issues we're concerned that the Exchange Server itself is banjaxed. We did raise a support ticket with MS who said they could see and confirm there was an issue, but didn't know how to fix it so closed and refunded the money. Ideally, we want to get it fixed, but are also looking at other options. The Exchange 2013 box is still active and running in co-existence. Would it be possible to install a fresh Exchange 2016 box and migrate everything to that? If so, would we still need to keep the Exchange 2019 even if it is not running any services? I understand that if you install Exchange 2019 from fresh this isn't possible, but unable to find any solid information relating to our particular situation. Any thoughts greatly appreciated! Thanks, Mark
