There are many reasons why you might want to connect the Project client to the server using an account other than the one that you typically use. In 2007 this was a relatively straightforward task accomplished using the “Enter User Credentials” option on the login box that opened when you opened up Project 2007. However in 2010 the login box now only allows you to select the server that you wish to connect to. That leaves you with a couple options for connecting to the server using a different account including using the “Run as Administrator” option from the context menu. However, in order to connect to the server using an alternate account and maintain the ability to use all features of the Project client (like creating and linking deliverables) you will need to change some settings in Internet Explorer:
Open the following dialog starting from the IE main page:
Tools > Internet Options > > Security > Custom Level
Where in the security zone in which the PWA is loaded, this can usually be determined by going to the PWA home page and looking at the bottom of the Internet Explorer window:
After clicking on the “Custom Level” button you should see a long list of security settings. You are looking for a setting near the bottom called “User Authentication” which you should set to “Prompt for user name and password” as shown here:
After you’ve accepted this change you can safely attach the Project Client to a server using any valid domain account and perform all expected functions. After you are done you might want to consider returning the setting to the original value as IE will now prompt you for credentials any time you connect to a site within that zone regardless of its association with the Project Server.