How to solve attachment issues in Outlook 2010

Hi Fiends, In my next article of Outlook series, I am going to discuss that how to solve attachment related issues in Outlook 2010. Kindly leave your valuable comment on same.

Attachment issues.

Sometime users face some issues when they are sending attachments with the emails or sometime when users are trying to open the attachments they also faced issues. So here are the some common outlook issues.

Problem description 1

When you use Microsoft Office Outlook 2010 or Microsoft Office Outlook 2007 to send an email message, the recipient of the message sees an attachment that is called Winmail.dat.


To prohibit Outlook 2010 from sending the Winmail.dat file

Add the DisableTNEF registry entry. To do this, follow these steps:

  • Exit Outlook 2010.
  • Click on Start & type Regedit and click on Ok to start Registry Editor.

Note: If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation.

  • Locate and then select the following registry subkey:
  • HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
  • On the Editmenu, point to New, and then click DWORD Value.
  • Type DisableTNEF, and then press Enter.
  • Right-click DisableTNEF, and then click Modify.
  • In the Value databox, type 1, and then click OK.
  • Exit Registry Editor.
  • Restart the computer.

Problem description 2

“Can’t create file: ‘FILENAME’. Right-click the folder you want to create the file in, and then click properties on the shortcut menu to check your permissions for the folder.”


Sometimes you may also experience the issues that attachments cannot be opened from within outlook (e.g. nothing happens when you double-click an attachment, although it is previewed correctly) but you can open it as soon as you save it to the desktop for example.

Another common issue is that you are not able to add attachments to emails. Again with various error messages you may come across.
You may also experience issues with just one filetype like *.xls for example whereas Word documents can be opened just fine.

Clear the contents of the OutlookSecureTempFolder!
And here is how to achieve this:
1.  Search the registry for the key “HKCU\Software\Microsoft\Office\12.0\Outlook\Security\OutlookSecureTempFolder”.


  1. Double click this key and copy the folder path to your clipboard.


  1. Open the path you just copied from the registry in Windows Explorer.


  1. Move all files (in case you want to play it safe) located in this folder to another location or simply delete them. (As those files are just temporary files that are created when you open an email attachment you usually can find another copy of those documents within your Outlook items)

    5. Close and restart Outlook.

Note: Whenever you open an attachment in Outlook (of a trusted filetype), a temporary file is created in the OutlookSecureTemp folder. Usually those files are automatically deleted as soon as you quit Outlook or close the attachment. However, sometimes those files are not removed as expected (e.g. when Outlook or your computer crash while an attachment was opened)



Arun Chaudhary


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