While on customer site today I got involved in a small support issue with attachments not opening in Outlook 2010. Right clicking on attachments did nothing, double clicking on attachments did nothing.
Firstly I looked in the event viewer and saw nothing related to any office errors.
Secondly, I ran a repair installation of office 2010 and soon after the issue reoccurred.
Thirdly, I tested further by attaching a plain text file to an email and sent it to themselves with the same result – nothing would open.
The only thing sitting between Outlook and the registered application for opening that file type was the Anti-Virus program.
This particular antivirus program didn’t offer a repair option in control panel so I uninstalled and reinstalled it and got them to retest – issue solved.
The hook between outlook and the antivirus must have encountered an issue and the only want to fix is was the uninstall/reinstall.
Hope this helps someone else, there wasn’t much on the web about it.