Problem:
When attempting to open documents on our sharepoint portal we are being prompted for credentials. cancelling the prompt allows the document to open. Later if the user clicks on “Edit Document” from the menu above the credential prompt reappears. While being prompted for credentials you can either enter them 3 times and the dialog goes away OR the user can click cancel. Regardless of the users actons, after clicking the “Edit Document” button a prompt is presented that says “Unknown Error trying to lock file”. This only happens on Windows Vista Clients
Solution:
Lets start with the first part….. When opening a document from MOSS on Windows Vista SP1 running Office 2007 the user is prompted for credentials.(You will need Vista SP1, Install it if you don’t already)
Apply the registry settings mentioned in the following article.
http://support.microsoft.com/?id=943280
Second Part…..
Install the following Hotfix – This fixes the prompt Windows XP users are accustomed to seeing when opening a document (The prompt reads “How would you like to open this file?”With the selectable options of “Read-Only” or “Edit”)
http://support.microsoft.com/KB/954809
Third Part……
Peter H mentioned this in his post previously
Set you Microsoft Office exe properties to run in Windows XP SP2 Compatibility Mode