近期公司做了一些系统升级服务，原有使用的是Exchange2010，然后想升级Exchange2013，但是由于考虑到服务的稳定及持续性，所以就在环境内部署了两台Exchange2013服务器，部署后，准备迁移用户的时候发现有点问题，在迁移用户的时候提示用户邮箱不存在，其实呢是真实存在的，所以在网上找一些解决方案，解决后总结了一下分享给有需要的朋友，我们都知道，从Exchange2013开始Exchnage的架构变化很大，从原有的CS架构变成了BS架构，所以关于Exchange的所有操作都是通过BS进行管理的，在Exchange2013开始管理登录脚面叫ECP(Exchange控制面板)，具体就不多说了，言归正传，我们在Exchange2013在ecp下迁移用户，提示错误，该用户没有Exchange邮箱，以下为解决方案。通过查看该问题出现的原因有以下三种可能： 

1.There are one or multiple system mailboxs in an inconsistent state because the HomeMDB attribute is missing

2.The Federated mailbox is in an inconsistent state because the HomeMDB attribute is missing.

3.The Discover Search mailboxes is in an inconsisten state because the HomeMDB attribute is missing.

https://social.technet.microsoft.com/Forums/zh-CN/7f891e85-8a87-49e5-bfe8-a03af256eea9/exchange-2013-ecp-exchange?forum=exchangeserverzhchs

http://blogs.technet.com/b/exchangesearch/archive/2011/09/20/discovery-search-fails-w-error-quot-the-user-does-not-have-an-exchange-mailbox-quot.aspx

所以我们使用以下命令查看问题所在的原因。

提示一下两个数据库有问题，缺少一个值

然后我们通过adsiedit来编辑修改信息

大概意思为：首先通过adsiedit下查看用户的HomeMDB值，然后编辑复制后，然后再通过users下的对应的错误的HomeMDB值进行粘贴

复制用户下的HomeMDB值后确认

然后我们在找到users下找对对应的错误的mailbox信息

此时我们右击属性

如果该页面不能够现实出HomeMDB的相关信息，我们可以单击筛选器进行设置现实状态信息

如果该页面不能够现实出HomeMDB的相关信息，我们可以单击筛选器进行设置现实状态信息

粘贴从用户那复制的信息，确认即可

如果存在站点部署的话，我们需要同步站点配置信息，让数据尽快保持最新，

同步后我们就可以测试通过ECP进行迁移了，最后迁移成功

以下内容为官网的详细步骤：

https://support.microsoft.com/en-us/kb/2702446

http://blogs.technet.com/b/exchangesearch/archive/2011/09/20/discovery-search-fails-w-error-quot-the-user-does-not-have-an-exchange-mailbox-quot.aspx

https://social.technet.microsoft.com/Forums/zh-CN/7f891e85-8a87-49e5-bfe8-a03af256eea9/exchange-2013-ecp-exchange?forum=exchangeserverzhchs

To resolve this issue, follow these steps:

1. Start the ECP.

2. Verify that one or more mailboxes are in an inconsistent state. To do this, type the following cmdlet, and then press Enter:

   Get-Mailbox -Arbitration |fl name, alias

   Note You may receive an error message that resembles the following. This error message confirms that one or more System mailboxes or the Federated mailbox is in an inconsistent state:

   WARNING: The object xxxxx/xxxxx/SystemMailbox{1f05a927-9daf-4003-9bf7-036822f96290} has been corrupted, and it's
   in an inconsistent state. The following validation errors happened:
   WARNING: Database is mandatory on UserMailbox.
   WARNING: Database is mandatory on UserMailbox.

3. Verify that the value for the HomeMDB attribute is missing for a mailbox. To do this, type the following cmdlet in the ECP, and then press Enter:

   Get-Mailbox |fl name, alias

   Note The following error message indicates that the value for the HomeMDB attribute is missing:

   Database is mandatory on UserMailbox

4. Copy the HomeMDB attribute value for a mailbox in the same database as the System mailbox, the Federated mailbox, or the Discovery Search mailbox. To do this, follow these steps:

   1. Click Start, type Adsi Edit in the Search programs and files box, and then press Enter.

   2. On the Action menu, click Connect to.

   3. Click Select or type a domain or server, click the server that you want, and then click OK.

   4. Expand Default naming context, and then click the following item:

      DC=domain,DC=com

   5. Double-click CN=Users.

   6. Right-click a user mailbox, and then click Properties.

   7. Under Attribute, click homeMDB, and then click Edit.

   8. Copy the value for the HomeMDB attribute, and then click OK two times.

5. Set the HomeMDB attribute value on the System mailbox, the Federated mailbox, or the Discovery Search mailbox account. To do this, follow these steps:

   1. In ADSI Edit, right-click the account for the System mailbox, the Federated mailbox, or the Discovery Search mailbox, and then click Properties.

   2. Under Attribute, click homeMDB, and then click Edit.

   3. Type or paste the HomeMDB attribute value that you copied in step 4.

   4. Click OK two times.

6. On the File menu, click Exit.

7. Replicate the forest. To do this, type the following at an elevated command prompt, and then press Enter:

   repadmin /syncall /e