Solving SharePoint 2013 incoming mails stuck in Drop folder

I was setting up Incoming Mails for SharePoint 2013 and like many people on Google, my mails were delivered to the Drop folder and were stuck there. I have solved this and have gained some insights into how Incoming Mails should be configured. This post captures these learnings.

Please note this is for SharePoint 2013 only.

1. My topology and Incoming Mails configuration

In the end the problem was because of a misconfiguration that was not appropriate for my topology. I will therefore first describe my topology and the original configuration.

I have a 4-servers farm with 2 WFEs and 2 Apps servers. The SharePoint Incoming Mails service is provisioned on both Apps servers. One of the Apps servers runs the Windows SMTP Service.

In Central Admin I configured Incoming Mails using the Automatic mode and specified to use Directory Management Service.

2. High level overview of how Incoming Mails works

This is necessary to understand the problem. If configured correctly, then when a mail is sent to Exchange, Exchange routes the mail to the SMTP Server that is specified in Central Admin’s Incoming Mails configuration. This ends up in the Drop folder of the SMTP Service on this server. A SharePoint timer job, namely Microsoft SharePoint Foundation Incoming E-Mail, monitors this folder and processes mails that are delivered to this folder. This timer job is responsible for creating items in your lists/libraries and removing processed mails from the Drop folder. This timer job is scheduled on all servers where the SharePoint Incoming Mails service is provisioned. It is scheduled to run every 1 minute by default.

3. The problem, root cause and the fix

As mails were being delivered to the Drop folder, we can exclude Exchange from the problem, and isolate it down to the SharePoint timer job. In my case, the root problem is because the timer job was not able to access the Drop folder to process delivered mails.

Recall that I have the SharePoint Incoming Mails service provisioned on 2 Apps servers (server A and B). This means that the timer job is scheduled to run on both of these servers. Recall that I also have the Windows SMTP service running on 1 Apps server (server A). This means the Drop folder is on server A.

In Central Admin I also configured Incoming Mails using Automatic Mode. This means SharePoint uses the Drop folder as specified by the Windows SMTP service. By default this is c:\inetpub\mailroot\Drop.

The root cause is because when the timer job is running on server B, it is unable to access the Drop folder on server A. This is probably because it attempts to access it using c:\inetpub\mailroot\Drop, which does not exist on server B.

I created a network share to the Drop folder on server A, switched Incoming Mails to Advanced Mode in Central Admin, and entered the share path (e.g. \\serverA\Drop) for the E-Mail drop folder setting and Incoming Mails immediately worked for me.

Be aware that you will need to grant appropriate permissions to the network share for the Central Admin’s app pool account, and the content web application app pool accounts as per the MSDN article on setting up Incoming Mails.

4. Understanding more about Incoming Mails

OK, so the timer job on server B could not access the Drop folder, but what about the timer job on server A? If the timer jobs are scheduled every 1 minute, the mails shouldn’t get stuck for a long time, right?

Well, this is where things got interesting.

By chance I noticed that even though the timer job is scheduled on 2 servers, it was only executing on server B as shown below.

1 Jobs

The job on server A would be rescheduled every 1 minute, but it’d never execute.

I found this post, which explains what’s going on. As a summary, while the timer job can be defined on multiple servers (i.e., on those servers where the Microsoft SharePoint Foundation Incoming E-Mail service is provisioned), it will only execute on 1 particular server. The server that it will execute on seems to be internally set when the Timer Service Recycle job (of the Microsoft SharePoint Foundation Timer service) is executed.

I tested this and it seems to be true. I ran the Timer Service Recycle job and the Microsoft SharePoint Foundation Incoming E-Mail job started executing on the other server (server A) and stopped executing on server B. I do not know how SharePoint picks which server to run the Incoming E-Mail job on.

The Timer Service Recycle job performs a graceful restart of the Timer service. You can read more about it here: The default schedule for this job is 6:00am daily. It is however disabled by default on my server.

5. Summary and Take Away

So when incoming mails are stuck in the Drop folder, it is likely because they are not being processed by the Incoming E-Mail timer job. In a multi-servers farm, it is best to create a network share to the Drop folder and use this network share in configuring Incoming Mails in Central Admin. This helps to ensure that the Incoming E-Mail timer job can access the Drop location regardless of where it is being run from in the farm. Ensure you have granted permissions to the network share as per the MSDN article on configuring Incoming Mails.


About Bernado

Based in Australia, I am a freelance SharePoint and Dynamics CRM developer. I love developing innovative solutions that address business and everyday problems. Feel free to contact me if you think I can help you with your SharePoint or CRM implementation.
This entry was posted in Incoming Mails, SharePoint 2013. Bookmark the permalink.

11 Responses to Solving SharePoint 2013 incoming mails stuck in Drop folder

  1. Deepesh says:

    i have 3 WFE Server and i have install SMTP on All Server , for smtp we have create alias
    and no drop folder shearing in SharePoint 2010 Farm,so my question is that can we used share path in SharePoint 2010? because of after Timer Recycle Job run some time my SMTP incoming Mail not send a mail to share point repo.when i have checked on one of my WFE drop folder the mail stored and not send .. and my timer job get stop so i have re boot the server and after that all services has running fine.
    does SMTP mail kill by sharepoint services
    does other custom services run as same time on recycle job has run..
    or any Bug in SharePoint 2010 Oct 12 CU Mailing Services stop or not send mail on time..

  2. Jake says:

    step 3 worked for me. thanks!

  3. Jens Nielsen says:

    Thank you so much for posting this, it was my exact problem.

  4. Pingback: Set Up Incoming Email to a SharePoint List | SharePoint 2010

  5. Adam Duggan says:

    Thanks for the info on Incoming Email timer job changes in 2013 and reference to Timer Service Recycle. That resolved my issue!

  6. Sajesh says:

    Thank you very much, I suffered a lot with this issue and finally step 3 gave me the success

  7. Fredrik says:

    Thanks! This solved out problem..

  8. Ruby says:

    Thanks!! Info was what I needed for my prod servers, for some reason QA is not behaving so nicely but at least I know it works properly in Prod. 🙂

  9. Devvon says:

    I love youuuuuu! This was my issue as well. There were so many blogs, posts, and whatnot, with the same issue, BUT all had different fixes! I tried most of them and none of them worked! Thank goodness I found your blog….it was explained so clearly and precisely! I think when discussing SharePoint/ScarePoint, you HAVE to be specific and spell out things….you were and you did.

    Thanks for all the info. Not only did it fix my issue but I learned a lot too! I’ve been an SP Admin for 1 year….9 months of which I was totally on my own learning this SP platform and Windows (and some SQL stuff too).

  10. Cano says:

    In my case i will selected Settings mode: automatic and not work, and then we will change to advanced and set E-mail drop folder to c:\inetpub\mailroot\drop and restart sharepoint timer services.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s