how to fix "the web server "Your Web URL" did not appear to have sharepoint foundation installed"

i already got this issue when i try to open the website via SharePoint  Designer 2010

"the web server "My WebSite URL" did not appear to have SharePoint foundation installed"

it is so strange since i can open the website  and interact with it in the browser

I google it and found a solution from microsoft http://support.microsoft.com/kb/981223

just following steps that i directly copy from microsoft website,

"

1. Start SharePoint 2010 Central Administration, and then click Security.
2. Click Specify authentication providers.
3. If the Web application in the Web Application list is not the same application that you want to open in SharePoint Designer 2010, click Web Application on the Change Web Application list.
4. On the Select Web Application page, click the name of the Web application that you want to open.
5. Under Zone, Click Default to open the Edit Authentication page.
6. Under Enable Client Integration, click Yes, and then click Save.

"

Reminder: as mentioned by Microsoft, the root cause of this issue is that The Client Integration had been disable. Though my site setting show that Yes check is checked,  i click the save button and then open the website in SharePoint designer 2010 successfully, i believe there is some configuration error that cause the Client Integration had been disabled.  the setting display the incorrect setting. i had to save it again to overwrite the previous setting.