Server error: Access is Denied When Using SharePoint Designer

Every once in awhile I get an annoying error in SharePoint Designer when I'm trying to copy files or check something in or out. The error only says "Server error: Access is Denied".

To fix this, I add my windows account to the Policies for Web Application in All Zones and give the account Full Control.

To do this, log in to Central Administrator and select the Applications tab. Click "Policy For Web Applications". Click "Add Users". Choose the right web application and All Zones. Click Next. Choose your user account and make sure it resolves using the People Picker. Give the account "Full Control" and click "Finish". Hope that helps other people.