Update October 16, 2026: For more information related to installation of October 2026 updates for Windows Server and the possible impact on Exchange Server, please see Exchange servers may become uns...
Updated Oct 16, 2026
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We have the same problem here, mail queues up. Windows 2019 Server and Exchange SE. Problem started showing today. Patch was applied yesterday. We also had a problem to transfer active databases for the server we restarted when we put it into maintenance mode. Never experienced this problem before.
A note, we also applied the October Windows updates for Windows 2019 Server
Had to restart mailservers today 16/10 again approx 20-22 hours after last reboot.
What errors did you encounter with transferring active databases - here, require re-syncing and remounting with one DAG database failed too !
Unfortunately i didnt write down the error but it had something to do with mapiexeption or something like that. Maybe this "
mapiexceptionnetworkerror unable to make connection to the server"
We simply just tried restarting the server were the databases indicated failed status. And after reboot the started syncing by themself. So i guess this issue was on both servers. But we hadnt figured it out until we read about all this here.Today. I had to restart both DAG members again because of the issue but this time i could transfer the databases by the maintenance mode procedure. No error. But this time i noticed it in "time". Its seems that the longer you wait after the 22 hours the worse the symptomps get.
This is a horrendous situation - spent a couple of hours being thorough with checks before coming here to find the answer was turn it off and turn it on again! the frustrating part being that as trying to drain the queues and migrate the active databases - the error occurs and then they show as dismounted / failed (for more panic to set in). I will keep an eye for the 20-22 hour mark, see if the errors returned.