Symptoms
In an Exchange Server 2016 environment in which drive D does not exist, an instance of event ID 6003 that resembles the following may be logged in the Application log:
SyncDelivery: Failed to create the log directory: D:\TransportRoles\Logs\Mailbox\SyncDelivery\Request
because of the error: Could not find a part of the path 'D:\'.. Logs will not be generated until the problem is corrected.
Cause
The issue occurs because the Mailbox Transport service creates log files that are not in the path of %exchangeinstallpath%\logging.
In an Exchange installation where there is no drive D, the log files cannot be created, and therefore event ID 6003 is logged.
Cumulative update information
For Exchange Server 2016
To resolve this issue, install Cumulative Update 4 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology that Microsoft uses to describe software updates.