New File Extensions Blocked in Outlook 2003 SP3

 

After several months of testing, a client recently deployed Service Pack 3 for Microsoft Office 2003 to nearly 10,000 clients via WSUS. They have a scripted routine that they follow during testing of patches and updates to ensure that there are no interoperability issues, but of course, you can't test everything. I mean, how are you going to know that a certain update will prevent an HP 4200 printer from feeding from the secondary paper tray? And yes, I've actually seen that happen.

Well, shortly after deployment they start getting complaints that emails with links to Public Folders (XNK files) can't be opened on Outlook 2003. Could it be that Microsoft actually did this on purpose? After an hour or so of re-reading all the scattered documentation for Office SP3, including Information about certain file types that are blocked after you install Office 2003 Service Pack 3 and the Downloadable list of issues that the service pack fixes, I couldn't find anything that documented this change.

I opened a case with Microsoft and found that not only are XNK extenstions blocked, but several others are as well. Here's an unofficial list of the extensions blocked by Outlook 2003 SP3:

File Extension	File Type
.ade	Access Project Extension (Microsoft)
.adp	Access Project (Microsoft)
.app	Executable Application
.asp	Active Server Page
.bas	BASIC Source Code
.bat	Batch Processing
.cer	Internet Security Certificate File
.chm	Compiled HTML Help
.cmd	DOS CP/M Command File, Command File for Windows NT
.com	Command
.cpl	Windows Control Panel Extension (Microsoft)
.crt	Certificate File
.csh	csh Script
.der	DER Encoded X509 Certificate File
.exe	Executable File
.fxp	FoxPro Compiled Source (Microsoft)
.gadget	Windows Vista gadget
.hlp	Windows Help File
.hta	Hypertext Application
.inf	Information or Setup File
.ins	IIS Internet Communications Settings (Microsoft)
.isp	IIS Internet Service Provider Settings (Microsoft)
.its	Internet Document Set, Internet Translation
.js	JavaScript Source Code
.jse	JScript Encoded Script File
.ksh	UNIX Shell Script
.lnk	Windows Shortcut File
.mad	Access Module Shortcut (Microsoft)
.maf	Access (Microsoft)
.mag	Access Diagram Shortcut (Microsoft)
.mam	Access Macro Shortcut (Microsoft)
.maq	Access Query Shortcut (Microsoft)
.mar	Access Report Shortcut (Microsoft)
.mas	Access Stored Procedures (Microsoft)
.mat	Access Table Shortcut (Microsoft)
.mau	Media Attachment Unit
.mav	Access View Shortcut (Microsoft)
.maw	Access Data Access Page (Microsoft)
.mda	Access Add-in (Microsoft), MDA Access 2 Workgroup (Microsoft)
.mdb	Access Application (Microsoft), MDB Access Database (Microsoft)
.mde	Access MDE Database File (Microsoft)
.mdt	Access Add-in Data (Microsoft)
.mdw	Access Workgroup Information (Microsoft)
.mdz	Access Wizard Template (Microsoft)
.msc	Microsoft Management Console Snap-in Control File (Microsoft)
.msh	Microsoft Shell
.msh1	Microsoft Shell
.msh2	Microsoft Shell
.mshxml	Microsoft Shell
.msh1xml	Microsoft Shell
.msh2xml	Microsoft Shell
.msi	Windows Installer File (Microsoft)
.msp	Windows Installer Update
.mst	Windows SDK Setup Transform Script
.ops	Office Profile Settings File
.pcd	Visual Test (Microsoft)
.pif	Windows Program Information File (Microsoft)
.plg	Developer Studio Build Log
.prf	Windows System File
.prg	Program File
.pst	MS Exchange Address Book File, Outlook Personal Folder File (Microsoft)
.reg	Registration Information/Key for W95/98, Registry Data File
.scf	Windows Explorer Command
.scr	Windows Screen Saver
.sct	Windows Script Component, Foxpro Screen (Microsoft)
.shb	Windows Shortcut into a Document
.shs	Shell Scrap Object File
.ps1	Windows PowerShell
.ps1xml	Windows PowerShell
.ps2	Windows PowerShell
.ps2xml	Windows PowerShell
.psc1	Windows PowerShell
.psc2	Windows PowerShell
.tmp	Temporary File/Folder
.url	Internet Location
.vb	VBScript File or Any VisualBasic Source
.vbe	VBScript Encoded Script File
.vbs	VBScript Script File, Visual Basic for Applications Script
.vsmacros	Visual Studio .NET Binary-based Macro Project (Microsoft)
.vsw	Visio Workspace File (Microsoft)
.ws	Windows Script File
.wsc	Windows Script Component
.wsf	Windows Script File
.wsh	Windows Script Host Settings File
.xnk	Exchange Public Folder Shortcut

Nothing p$%#es me off more than undocumented changes in functionality. At this point in time, this information is not documented ANYWHERE on Microsoft's website.

I certainly don't mind Microsoft fixing security holes, but for crying out loud, DOCUMENT IT!!! How do they expect us to roll out critical patches and updates if they change functionality and don't tell anyone? No one looks good when that happens.