This type of error has been popping up more and more frequently with some of our clients.  It’s caused opening multiple attachments in Outlook that have the same file name.  Outlook’s secure temp folder fills up with these files and throws this error when you have 100 files with the same name.  This folder is really difficult to find on your own (it takes digging around in the registry to find it), this tool simplifies the purging and you can even set it up via scheduled tasks to do it automatically.

OutlookTempCleaner has a minimal interface.  Just double click the icon, then press “Clear Folder” and it’s done.  If you want you can also open your secure temp folder before running it just to be sure you’re not going to lose anything.

It works with all versions of Outlook going back to Outlook 2000 and even works on the Outlook 2010 beta.

As an IT administrator you can also script it to run on logon/logoff or at specific intervals via command line switches such as
-clearfolder to delete all files located in the temp folder
-openfolder to open the folder
-foldersize to display the size of the Outlook temp folder

Check it out here