I was able to take a few days off just prior to the July 4 holiday weekend. As most of you can surmise, I don't take a lot of time off, so this was the first time I had actually experienced this particular bug in the Mail app for Windows 8.1.
As my first day off approached, I set my Out of Office message in the Mail app for Windows 8.1. Setting it worked just fine, but getting rid of it was another story altogether.
When you set your Out of Office message, everything works as you would expect. I checked in the Automatic Replies section of OWA and verified that the settings had, indeed, been set correctly. But, each time an automatic reply was sent using the Windows 8.1 Mail app, a message popped-up on the screen telling me that the configuration couldn't be saved. So, while everything actually worked (and the setting was truly saved), Mail was confused and the pop-up message became more than annoying.
I sought a fix for the problem, and after digging into it in the Microsoft web-based forums, I realized that this is a common bug. Many have experienced the same issue and so far the only fix is to completely remove the account from the Mail app and then set it back up. Fortunately, because it's an Exchange account, nothing is lost and if the email admins have used standard server settings, account setup is quick and automatic. Still, it does take some time for the Inbox and selected folders to resync. And, if the Exchange admins have altered mail port numbers and used different server paths, then I imagine resetting the account could become a nightmare.
Apparently, this bug goes back for some time, with the first reported occurrences posted in October 2013. There have been many updates to the Mail app since then, but none of those updates have addressed the bug. Let's hope Microsoft takes notice and fixes this one soon. It's not app-ending, for sure, but the annoyance is beyond belief. And, who really wants to delete and reconfigure a mail account constantly?