In attempting to prepare for a module I am teaching tomorrow, I am putting Click Once through its paces, and I'm finding there are some strange issues. I have been struggling with an unusual error for half the night.
I am Publishing my files to a local site, then openning up internet explorer, navigating to the site and then attempting to Install the application. The application contains a 4 files that require downloading, and it uses SQL Server Express. The Install starts out fine, it then decides it needs to momentarily open a browser window. Now my default browser is Fire Fox, and it decides to open this. At this point firefox decides to prompt me for a username and password. Why I don't know, but seconds after typing in my credentials, it brings up an error saying that it cannot download the application as there are missing files. The install fails.
I eventually figured out that if I change my default browser back to be internet explorer, the problem goes away. Hope this helps someone.