Update November 8 2012 This issue was fixed in both Outlook 2007 and Outlook 2010 by recently released hotfixes.
Outlook 2007: install the Word 2007 hotfix in Description of the Word 2007 hotfix package (Wordconv-x-none.msp, Word-x-none.msp): October 30, 2012
Outlook 2010: install the Word 2010 hotfix described in Description of the Word 2010 hotfix package (Word-x-none.msp, Kb2428677-x-none.msp): October 30, 2012
We're seeing complaints that Outlook is adding duplicate extensions to attachments.
Outlook 2007 is adding .pdf to an existing .pdf file. How do I stop this? When I add attachments to messages or forward a message with an attachment, the extension is duplicated. For example, my-file.pdf becomes my-file.pdf.pdf.
All file types are affected, not just .pdf. Each time the attachment is forwarded, an additional extension may be added.
This is the result of a recent update. The problem updates are KB2687315 (Office 2007) and KB2553488 (Office 2010).
These are updates address critical issues in Microsoft Security Bulletin Summary for October 2012 and patch vulnerabilities in Word for which active exploits.
Microsoft is investigating and is expected to release an update to this update.
Workaround: Drag the attachment into the attachment field of the new email and no extra extension is added. Because the attachment field only shows up after you add an attachment, you need to add an attachment, delete it then drag an attachment into the attachment field.
Published October 23, 2012. Last updated on June 7, 2021.