My IT Experiences - Microsoft 365, SharePoint & Azure

This is a very common that we get authentication dialoge box while trying to edit an Office document on a SharePoint library from Internet. This happens even if you are logged in to your site using browser. It is frustrating for end user because he/she has provided credentials once before loggin in to the site and now when tried to open/edit a document (Word, Excel etc) again the credntial window pops up. Quoting Microsoft: "When Internet Explorer opens an Office document, the appropriate Office application is started with the path of the document. The Office application then tries to access the document directly from the server. This differs from other browsers and other file types. Most browsers download the file and call the application to open the file from the local cache. However, when this occurs, if the opened file is changed and saved, the changes are only made to the local copy and not to the server copy. To establish the richest experience possible, the first thing that...

I got this error while trying to browse my SharePoint site from within the server. I tried in both my front ends and application server and got the same error. I double checked to make sure the user I'm trying to login to the site had enough permission and also that password had not expired or account locked. Nothing seems to help. Then I came across this excellent article by Spencer Harbar which talks about this issue. This error is caused by a feature in Windows Server 2003 SP1 and above called loopback security check. This feature prevents access to a site using its FQDN (Fully Qualified Domain Name) from the server that hosts the website. Here is Spencer's blog post: http://www.harbar.net/archive/2009/07/02/disableloopbackcheck-amp-sharepoint-what-every-admin-and-developer-should-know.aspx There is also a Microsoft KB article that gives a solution to this problem. There are two solutions, disable loop check through a registry entry (not recommended for production servers) ...