I have just upgrade a working portal to version 6.1.1 and the upgrade went smoothly and reported no errors.

Unfortunately, when I try to access any of the portals within this install that page starts to display but before finishing the page will refresh and load from the start. Using IE 9 there is not enough time to log in or even see the page contents.

Using FireFox the refresh is slower and I can click on the menu items or see the log in page but it still refreshes too quickly to actually log in.
One interesting item on the Log in screen is that it displays first with the "Lock" icon and then on the next refresh it displays without any images showing then it goes back to displaying the Lock image.

One other item of note is that I can go to the register.aspx page and it will display properly without the refresh issue.

I have checked in the EventsLog and SiteLog tables and see no messages that provide any clues.

Any thoughts?

I have tried it from several different computers with different OS, different browsers, etc but always get the same result.  The only variation is how fast the page refreshes.

UPDATE 2:

Once I log in , I can change the web.config so that the clientDependency section is enabled again and the site will then display and work as expected. 

BUT, once I log off then the pages refresh automatically as before.

Is there some sort of setting that would effect this??