This post belongs to my issue described here which I have not found a solution to yet. Except from one of the issues: the login prompts!
When you run a Vista client against your SharePoint site that you have installed on a Win Server 2008 then you are in trouble. First thing: dont run Vista, but if you do, then you will have the following issues:
1) you get three (!) login prompts when you want to open, edit or modify stuff on your site
2) you cannot map network drive
3) you cannot open a library in explorer view
But, yesterday I laborated and found that there is a solution to nr 1 – the login prompts. If you stop the WebClient service on your Vista client, add your site as a Local intranet in IE and set your LAN settings in IE to “Automatically detect settings”, the login prompts will disappear!!
If you don’t set your WebClient service to manual then you have to stop it each time you restart the PC so remember to turn it off and not just stop the service.
I will register a case at MS to find a solution for the other issues.