This article was been published more than a year ago. The information may be outdated.
Early this year, a user called in with a somewhat peculiar story. They had previewed a file attached to an email, and the subsequently deleted the email. It wasn’t important enough to be worth it to restore the entire mail file, and so they wondered if there was any other way to find the attachment. They noted that they had previously gotten into a folder which seemed to contain all previewed files, though they were unable to find it again when searching. The user had searched the web, to no avail, and so turned to me with two questions. First; could I help them find the folder, and second, why did it not show up in search.
I figured that Outlook had some mechanism to cache files locally, and that set me on the track to eventually find the content.outlook folder which is just that. The folder is located at
C:\Users\"userid"\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.Outlook\. It is not accessible by browsing to it (a clue to the answer to question two), and you must input the entire path to access it. Question one answered, I stumbled upon this thread, which had the answer to question two, as follows:
As it turns out, desktop.ini tells the OS to treat this folder as a history folder, rather than an ordinary one. This removes it from search, and changes how information in it is treated in explorer. As Jerry Perkinson put it in the aforementioned thread:
Question: Why does the content.outlook folder in ways that don’t make sense?
Answer: Because the desktop.ini file in the folder tells the OS to treat the folder as a “history” folder which normally acts in the strange way described. If you edit the file and remove the UICLSID line, it treats it like a normal directory. If you delete the file, it does the same, but the desktop.ini file returns on reboot.