Outlook 2010 corrupts all Office attachments on a Server 2008R2 Remote Desktop Server

Question

I have a rather annoying problem with a clients new Remote Desktop server.

The problem is that any and all Office attachments (tested with Word and Excel documents) sent to the users via email cannot be opened due to the file seemingly being corrupted/damaged.

I have determined that it is a local problem on the server, as the attachments work fine on my own pc. Also I believe the problem is isolated to Outlook, as the users can open already stored Office files without any issues.

What are your thoughts on this?

Extra information: The server is running Microsoft Server 2008 R2. The Office is a version 2010. It is handeling the roles of AD and RDS - The client only has one server, hence the breach of best practise. There is currently no AV software on the server. I have tried running a repair as well as a reinstalling of Office, with the error still there.

Solution

I know what you're talking about. I've just solved the same problem.

The Problem has got something to do with ADS (alternate data streams) in NTFS. It seems that an Outlook attachment is categorized as coming from the "Security Zone" "Internet", which is zone number 3. This categorization prevents Outlook in collaboration with other Office applications to open these attachments.

I found an interesting post by Phatsta on Ars Technica which helped me to solve the problem on a Server 2008 R2 using the following steps:

1) Office Application Security Settings

Every user needs to untick the following checkbox in Word 2010, Excel 2010, PowerPoint 2010, Publisher 2010, Access 2010, ... :

File > Options > Security center > Settings > Protected view > "enable protected view for attachments in Outlook"

2) Registry Keys

For every user there need to be 2 string values at the following location of the registry (e.g. via group policies):

HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security

The string values are:

name: "Level1Remove", value: empty
name: "Level2Remove", value: empty

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My users can work now. Good luck to you!