This Error event indicates that DSProxy.dll is missing or could not be found. If DSProxy.dll cannot be found, the Microsoft Exchange System Attendant service may not start.

To resolve this error, follow these steps:

• Make sure that DSProxy.dll exists on the Exchange server that logged this event. Follow these steps:
  
  
  1. Open Microsoft Windows Explorer.
     
     
  2. Locate C:\Program Files\Microsoft\Exchange Server\v14\Bin and confirm that DSProxy.dll exists.
     
     

     Note:
     If you specified a different install location when you installed this Exchange server, open the Bin directory of that location.

• Confirm that the HKLM\SOFTWARE\Microsoft\ExchangeServer\v14\Setup registry key has the required permissions. Follow these steps:
  
  

  Caution:
  Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.

  1. Start Registry Editor (regedit).
     
     
  2. Locate the following registry key: HKLM\SOFTWARE\Microsoft\ExchangeServer\v14\Setup
     
     
  3. Right-click the registry key, and then click Permissions.
     
     
  4. Click Advanced.
     
     
  5. Make sure that the Include inheritable permissions from this object's parent check box is selected.
     
     
  6. Use the following matrix to verify that the HKLM\SOFTWARE\Microsoft\ExchangeServer\v14\Setup registry key has the required permissions:
     
     

     Administrator, Domain Admins, Enterprise Admins, Exchange Organization Administrators and System	Full Control and Read access
     <MachineName>$, Exchange Domain Servers, Exchange Servers, Exchange View-Only Administrators and Users	Read access
     Creator Owner	Special Permissions
     Power Users and Terminal Server User	Read and Special Permissions

• Make sure that the Services REG_SZ registry entry under the HKLM\SOFTWARE\Microsoft\ExchangeServer\v14\Setup has the correct path of the DSProxy.dll file. Follow these steps:
  
  
  1. Start Registry Editor.
     
     
  2. Locate the HKLM\SOFTWARE\Microsoft\ExchangeServer\v14\Setup.
     
     
  3. In the result pane, double-click the Services registry entry.
     
     
  4. In Edit String, make sure that the Value data box contains the following value: C:\Program Files\Microsoft\Exchange Server\V14.
     
     

     Note:
     If you installed this Exchange server in a different location, make sure that the Value data box contains the path to that location.

If you are not already doing so, consider running the Exchange tools created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.