I have a sharepoint internal website that users connect to for documents and announcements and such. The problem I'm running into is that if they browse to a document library and try to open a file, it prompts for their username and password again. This only seems to happen if it's an office document as pdf files open without prompt. I should mention that authentication is based on active directory, but the clients are NOT local and connecting through a VPN. Because they're remote, they don't actually log into the domain. Is there a way to cache their credentials so that they only have to log in one time when they enter the site, or is there a setting somewhere that I missed?