Msftefd.exe process crashes if an email attachment has an unexpected file name extension or no file name extension in an Exchange Server 2010 environment

Applies to: Exchange Server 2010 StandardExchange Server 2010 Enterprise


Consider the following scenario:
  • You have an environment that has Update Rollup 4 for Microsoft Exchange Server 2010 Service Pack 2 (SP2) or a later update rollup that is earlier than Update Rollup 6 installed. 
  • You send an email message that contains an attached Open Office XML document (for example, a .pptx or .docx document) that is missing a file name extension. 
In this scenario, the Microsoft Full-Text Engine Filter Daemon (Msftefd.exe) process crashes. Additionally, the following events are logged on the Mailbox server:


This issue occurs because the incorrect file name extension causes a crash when the Exchange search engine indexes the email message.


To resolve this issue, install the following update rollup:
2746164 Description of Update Rollup 6 for Exchange Server 2010 Service Pack 2


To work around this issue, follow these steps:
  1. Click Start, click Run, type regedit in the Open box, and then click OK.
  2. Locate and then select the following registry subkey:
  3. On the Edit menu, point to New, and then click DWORD (32-bit) Value.
  4. Type NeverOverrideAttachmentExtension, and then press Enter.
  5. In the Details pane, right-click NeverOverrideAttachmentExtension, and then click Modify.
  6. In the Value data box, type 1, and then click OK.
  7. Exit Registry Editor.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about the Msftefd.exe process, go to the following website:For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2713339 Multi-Mailbox Search feature returns incorrect results when you perform a complex discovery search in an Exchange Server 2010 environment