We used to use ActiveSync extensively when it was all we had to work with (waiting for MAPI since it was being kicked around for v15 and having used SM since v3 alongside Exchange) but the wrinkles in EAS were becoming grave, particularly with large mailboxes and especially so if sub-folders were created within the Inbox rather than peer to it. Following some of what Tim was suggesting we spent a fair bit of time mining support info at MS and it was clear that they weren't necessarily SM problems and that Microsoft didn't intend to support EAS in upcoming versions of Outlook.
No rant here, if EAS were supported it would solve some problems for us but at this current Microsoft link (13FEB2022, see below) they do seem to suggest that EAS is not supported in Outlook 2022 when connecting to an Exchange server. You are right though, it looks like it is back in the list of possibilities when you configure an account but included for other purposes.
There is quite a bit of related information posted elsewhere here and in the knowledgebase. After putting many hours into investigating and looking for the best way to try to limp along with EAS to support Outlook functionality beyond what IMAP and the old "Add to Outlook" option used to provide, I came to the understanding that Microsoft would not move forward with EAS for Outlook and that, as a result, Smartertools could not move forward with it. It was that simple - a brick wall.
I suspect that if it has worked well for you in other versions recently it has to do with the work that ST have been doing on supporting some of the EAS updates intended for Smartphones since we abandoned trying to use it with Outlook.
Previously, I have seen a symptom very similar to what you are describing. When we tracked it down, the emails hadn't actually been removed from the desktop, they had been removed from display on the desktop. It was pretty much consistent that it would happen when the users opened Outlook but would also happen at other times while they were using Outlook, particularly with large mailboxes and either large incoming mail volume to the inbox or a large attachment within a lower volume. It was caused by Outlook rebuilding the index.
We found two things that would improve things significantly on a typical desktop with many applications open in addition to Outlook:
- Upgrade the users workstation to at least include an SSD but ideally more memory and, if possible, a faster CPU, especially for users with large inboxes.
- Very regularly perform preventative maintenance on the Outlook data file. We found that on a variety of high performance and lower performance Windows systems using Outlook and EAS you couldn't go more than a couple of days without the repair tool detecting at least some corruption. Even the free tool from Microsoft, SCANPST, will do the trick and if you can't upgrade the users systems we found this quite helpful on all but the very large mailboxes. At one point we were able to automate and schedule it. It may still be possible but broke after an Office update a while back.
In the end though, there are many things that the EAS protocol simply doesn't support/transport and, as a result, that SmarterMail can't provide. The best we found we could hope for, when the moon was full and the stars aligned, was an Outlook email client that was acceptable to users that weren't power users and hadn't had experience with Outlook connected to an Exchange server. The list of things that can fail, and were failing, when using EAS with Outlook is extensive (documented here and at MS). Given that MS haven't supported it for several versions, and seem to be moving in another direction for their own use with Outlook on mobile devices, we felt that we had to either move power users onto Exchange (Smarter handles splitting the accounts between servers quite well) or stop putting the solution forward as an Exchange Alternative until enough of our voices were heard that Smartertools made the HUGE investment into integrating MAPI. With it, they now support a protocol that will allow them to do most, if not all, of what power users used to using Outlook on Exchange have come to expect. It's clear that ST are listening as differences are pointed out and trying to enhance the Outlook experience.
By all means reach out, open a ticket or ask Tim to comment, but unless my understanding is significantly incorrect, you will not be be able to offer this enhanced Outlook experience, or the level of reliability SmarterMail is capable of providing, unless you get on the MAPI bandwagon. There is no competitive future for your Outlook offering down the EAS path you are treading and Microsoft may very well turn it off again within Outlook and without notice leaving you with a nightmare scenario when your users arrive after an update one morning and cannot connect to the server. I came to believe that this really was outside anything ST had control over. I think it took some time for them to reluctantly come to that same conclusion.
Finally, and just a wild guess, you might want to look at Microsoft's new man-in-the-middle approach to connecting Outlook mobile to on-prem and hosted servers. ST have commented on it extensively. If, by selecting EAS from within Outlook 2022, you end up accepting this, there are a number of other things that can go wrong. I'm not sure about the current version of Outlook but during some of the revisions in some releases of Outlook 2019 (Outlook acquired under 365 Apps for Business for example) this was the case and there were some registry hoops/hacks you needed to go though to work around it. With it in place, Outlook did not work well with the SM version at the time or even with an on-prem Exchange server. That same installation of Outlook would work as well as could be expected, once the registry changes were in place, the account deleted and re-created so that it connected directly to the SM server or on-prem Exchange server. This is just a guess but might be worth exploring if you are going to put time into looking to improve things without moving to MAPI.
I look forward to any light you shed in an additional post.