Microsoft ties the Cannot create file error in Outlook to the temporary folder for attachments. Outlook cannot clear that folder while attachments remain open. Fix it with a valid folder path in the OutlookSecureTempFolder registry value. Microsoft documents this for Outlook 2003 to 2010 only. Save a registry backup before any edit.
Outlook refuses to open or save an attachment and shows an error about creating a file. Microsoft documents the cause and the registry fix in two Learn articles.
Facts follow the Microsoft Learn article on attachment issues in Outlook and the article on pictures shown as a red X. Microsoft marks both as archived and names Outlook 2003, 2007 and 2010. Outlook 2013 and later are not named.
What is the Cannot Create File Error?
Microsoft quotes this message when you open or save an attachment. Cannot create file: file name. Right-click the folder that you want to create the file in and then click Properties on the shortcut menu to check your permissions for the folder.
Two other symptoms come from the same cause. Attachments remain in the Outlook Secure Temporary File folder after you exit. Outlook gives no prompt to save changes when you open an attachment from the Reading pane and exit.
What Causes the Attachment Error?
- Open attachments. Outlook cannot delete the temporary files or folders while the attachments are open.
- Server folder. Temporary Internet Files folder sits on a server where you lack permissions.
What is the Secure Temporary Folder?
Outlook stores safe attachments in a subfolder of Temporary Internet Files when you open them. Outlook first looks for the OutlookSecureTempFolder registry value. If the value is missing or points to a folder that does not exist Outlook creates a randomly named subfolder instead.
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security
Value name: OutlookSecureTempFolder
Data type: REG_SZHow to Fix the Registry Value?
- Create a registry backup first. Microsoft links Microsoft Support article KB 322756 for the method.
- Press Windows key and R, type
regedit.exeand press Enter. - Open the Security key for your Office version.
- Double click OutlookSecureTempFolder and check the path in File Explorer.
- Set a valid folder like
C:\temp0when the folder does not exist. - Create a string value with that name and a valid path when the entry is missing.
- Restart Outlook.
What About Newer Outlook Versions?
Microsoft states the problem is resolved in Outlook 2010 Service Pack 1 and in the Outlook 2007 hotfix package dated June 29, 2010. Neither article names Outlook 2013 or later. Treat these steps as history and test on a copy of the registry key.
Related reading: why Outlook blocks some attachment types and how to delete an attachment from an Outlook email.
Frequently Asked Questions
Why Cannot Outlook Open an Attachment?
Microsoft names two causes. Open attachments stop Outlook clearing its temporary folder or the Temporary Internet Files folder sits on a server without your permissions.
Where does Outlook Store Opened Attachments?
Outlook stores them in a subfolder of Temporary Internet Files. Set the path with the OutlookSecureTempFolder registry value.
Which Outlook Versions do These Steps Apply to?
Microsoft names Outlook 2003, 2007 and 2010. Both articles are archived.
Is Editing the Registry Safe?
Microsoft warns that serious problems occur if you edit the registry incorrectly. Save a registry backup first.
Key Takeaways
- Cannot create file errors come from the temporary attachment folder.
- OutlookSecureTempFolder sets the folder path.
- Missing or invalid paths break attachments.
- Microsoft documents this for Outlook 2003 to 2010.
- Create a registry backup before any edit.
Sources and References
Facts follow Microsoft Learn.
- Attachment issues in Outlook (Microsoft Learn) learn.microsoft.com
- Pictures not displayed and shown as red X (Microsoft Learn) learn.microsoft.com