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

CTO @ Golden Five | CEO at LAExUG Foundation

Prabhat is 3 times Microsoft MVP Award winner. He is MBA in Information Technology and he is working as a CTO at Golden Five Consulting which is a Microsoft Gold Partner, MSP, T1CSP, and Education partner. He helps in designing, implementing, managing and supporting solutions for private messaging cloud, mergers, a collaboration between different messaging software and other migration & deployment projects for the following technologies Office 365, Azure, AWS, Exchange, SQL, ADFS, MFA, FIM, MIM and Directory services. He has worked for all big IT giants either as an employee or contractor where he has led the Global teams. He has started his career as Technical Consultant in Exchange 5.5 with Microsoft PSS and his exchange love never stopped & continued with 2000/2003/2007/2010/2013/2016/2019/O365. At one point in time, he was the only person to support EDS customers when Microsoft had closed all the supports for 5.5 and now for all old legacy Exchange versions.
He used to blog at, manages multiple LinkedIn and Facebook Groups. He also Owns MSExchnageGuru YouTube channel where he uploads all his records technical sessions. Don’t forget to check his PowerShell scripts which are making admins life easier. Prabhat can be reached at

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