Hi @Andrei Corovin ,
but not on Windows 10 Enterprise LTSC 1809 machines. The pop-up doesn't appear!
Did this issue happen to all users working with Windows 10 Enterprise LTSC 1809?
And did it occur with all messages sent to all mailboxes in your Outlook client?
Based on my research, there seems to be no related known issue in the list of Windows 10 Enterprise LTSC 1809, but as I know, certain settings in Outlook and Windows may affect the feature of desktop alert, please first try to troubleshoot by the steps below:
- Firstly, it is worth mentioning that if the issue only occurred during the initial synchronization of an email account or when you request a manual Send/Receive, it's by design as the official article mentioned.
- Also, in the point of Outlook client, only the messages sent to default Inbox could display the desktop alert by default, please first check if the issue only happen to any specific messages that was moved to other folders by client rules.
- Then, the feature could also be affected by the setting in Outlook, please check if you have enabled this feature by the steps below(File>Options>Mail>check "Display a desktop alert" option under the message arrival)
- If the issue still exists, it's suggested to check if you have enabled the notification of Outlook in Windows settings(Start>Settings>System>Notifications & actions > Outlook)
Hope that would be helpful to you and if your issue has any update, please feel free to post back.
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