If you’ve ever run into the error message below when trying to open an attachment in Outlook, we have a couple of solutions you can try. The error message might only happen when trying to open certain file types and it’ll say that it cannot create the file and suggest that you check file permissions.
The issue is because of a permissions problem in the Outlook Secure Temp Folder (OutlookSecureTempFolder in the registry).
The first solution is to delete the Outlook Secure Temp Folder and let Outlook re-create it.
To do this, close Outlook, then go to Start and Run. In the run box, type in:
%localappdata%Temporary Internet FilesContent.Outlook
When you press Enter or Ok, Explorer will open the folder. Delete whatever files or folders are in this folder.
Finally, re-open Outlook and try to open your attachment again.
This option is a little more in-depth and requires editing the registry.
You’ll want to create a temp folder somewhere on your computer and remember its location. C:Temp would be simple.
Then go to Start and Run and type regedit.exe and hit Enter or Ok.
For Outlook 2010: HKEY_CURRENT_USERSoftwareMicrosoftOffice14.0OutlookSecurity
For Outlook 2003: HKEY_CURRENT_USERSoftwareMicrosoftOffice11.0OutlookSecurity
For Outlook 2007: HKEY_CURRENT_USERSoftwareMicrosoftOffice12.0OutlookSecurity
From there, double click on the OutlookSecureTempFolder key and change the value to C:Temp (or wherever you created your temp folder).
Close the registry and reboot.