Duplicate File Extensions appearing on attachments in Outlook.
We recently noticed a sudden increase in these this appearing in our spam traps.
I has been causing serious delays to essential emails as they get quarantined as suspicious which in itself is a good thing except these are not unsafe attachments.
It got so bad that one of our clients got so irate they threatened to kick us out unless we fixed it! All we could do was dumb down the AV settings whilst trying to work out where they were coming from?
3 Weeks later we eventually managed to recreate the issue!
IF a user drags an attachment from one email directly into a new one Hey Presto! Outlook instantly adds the file extension again.
Each time adding another Extentions.
So after a document has been passed around you can end up with mydocumentname.docx.docx.docx etc!
It turns out that yet another Microsoft Security patch rolled out in the October patch Tuesday is responsible.
MS are now aware and are looking into the issue but as yet have no solution. Uninstalling the last Office 2007/2010 updates is a work around.
Outlook 2010 dragging attachments appends extra extension