On Vista or Windows 7 you get "This file is read-only" when editing a SharePoint Services 3.0 document

Problem:

Using Vista, Office 2007 and Internet Explorer 7, or Windows 7 Office 2007 and IE8, you get any of the following errors when trying to edit and save a document from a SharePoint Document Library, or any other WebDAV based service.

• 
  This file is read-only.
  
• 
  Unknown error trying to lock file.
  
• 
  This document was checked out to your local drafts folder but the local copy could not be checked in to the site. Close any application that is editing the document and try to check in again, or discard the checkout.
  

Cause:

This problem is caused from a Vista and Windows 7 WebDAV problem when you do not have a Proxy Server defined.
Refer to Microsoft KB Article 943280.  Please note if Service Pack 1 for Vista is already applied then you only have to perform the  Registry change shown below.

Resolution:

Please follow the steps in the KB article above.
Step Summary

1. 
   Start - Run - RegEdit
   
2. 
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
   
3. 
   From top menu select Edit
   
4. 
   New - Multi-String Value
   
5. 
   Enter:   AuthForwardServerList
   
6. 
   Press ENTER
   
7. 
   From top menu select Modify
   
8. 
   In the Value Data box type:
   

http://YourSharePointApplicationURLs

Then reboot.

Published: 2/15/2008 9:21 PM