You do not have permission to open this Web site in SharePoint Designer

 

Theses are the Steps in troubleshooting this issue:

  1. Make sure the user have a Designer, Owner, or Administrator rights to the target site collection or web site.
  2. Make sure the site collection settings for designer are enabled.
    • Open site collection  settings.
    • Select SharePoint Designer Settings under the Site Collection Administration tab.
    • Make sure all options are enabled.

! Make sure you are not using any account running SharePoint services.