Exchange 2019: New Deployment Using D drive

Today a customer called with the Exchange 2019 mailflow issue.


Mailflow issue and D drive unavailable.


  • Upon checking we found all services were running.
  • This was the only exchange 2019 server on a windows 2016 active directory.
  • Database was mounted.
  • Outlook emails were stuck in the queue to Mailbox.
  • OWA emails were going to the draft.
  • When I check the event view I got the following strange event log.

    DnsErrorLog: Failed to create the log directory: D:\TransportRoles\Logs\Mailbox\DnsErrorLog\Submission\ because of the error: Access to the path ‘D:\TransportRoles’ is denied. Logs will not be generated until the problem is corrected.

  • When you don’t have a D drive and you see this, you will be clueless.
  • This was a new deployment and I asked the customer to give me a 100 GB D drive.
  • We created D drive and Created TransportLogs Directory and we could see logs started coming.
  • This above solution was part of the resolution but not a complete solution so emails were not flowing.
  • Now when we did the nslookup, server name was unknown.
  • Then we saw the error in the events and queue that DNS server is unable to find the domain.
  • Found customer has added public DNS in the TCP/IP settings of the exchange server.
  • Removed public DNS from exchange server and mail flow started working.

Next Step:

  • Told the customer to add public dns in DNS forward of the Active Directory DNS.
  • Still I had the question in my mind that why default log files are going to the D drive.
    • So, I tweeted to Director of Product Marketing for Exchange Server and Exchange Online – Greg Taylor

  • Now I am waiting for Greg to Respond.

Prabhat Nigam
CEO @ LAEXUG Foundation | CTO @ Golden Five Consulting

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